Showing posts with label betta splendens. Show all posts
Showing posts with label betta splendens. Show all posts

Research Paper to Read: (2014) The Study of Different Foods on Spawning Efficiency of Siamese Fighting Fish (Species: Betta splendens, Family: Belontiidae)

Source: ResearchGate.

What are the key point here?
(1) There is no significant differences between live feeds (Artemia, Blood worm, and Gammarus) and artificial feeds in Betta sp. breeding.

Why this paper?
As fish diet is a crucial nourishment for the brood stock in conditioning Betta sp. for breeding. What are the possible best food available to obtain a large spawn? Having a large spawn increases the breeder farm profits as the farm owner sell more fishes. This question have been asked numerous time in online forums and the general consensus among the breeders is use live foods with high protein nutrients. However, obtaining and culturing live feeds do incur additional costs and labour. Thus, through this paper, we would like to know what are the significant differences in using different foods and if those differences worth using it. (Note: This is not a the best written paper but we are always curious about the materials and methods used in breeding. Either it reconfirm our understanding or raises further questions regarding our current approach.)

Material and Methods
This experiment was conducted in a commercial fish farm which produces 50000 fishes annually. The material used are 20 aquariums, 40 fishes, 5 different fish feeds with 4 replicates as shown below. The dimension of each aquarium is 40cm x 30cm x 30cm with water height around 15cm, which is 18 litres. (Note: Not sure about the 'mass', assumed it refers to a group of egg.)

(1) Artermia cyst x 4 pairs.
(2) Artermia mass x 4 pairs.
(3) Blood worm x 4 pairs.
(4) Gammarus mass x 4 pairs.
(5) Commercial food x 4 pairs.

The water parameters of the breeding tank as below:

(1) pH: 7.5.
(2) Air temperature: 30 - 35 Celsius.
(3) Water temperature: 26 - 28 Celsius.
(4) Hardness: 108 ppm.
(5) Dissolved oxygen: 6 mg / litre.

The breeding procedures as follows:

(1) The breeding tanks were disinfected with salt without iodine.
(2) Fishes were disinfected using solution of 5% Acrofelavin bath for 5 minutes.
(3) Once the brood stocks were added to the breeding tank, it's not feed for 24 hours.
(4) A glass screen was added between the pair of fishes.
(5) Fishes were fed twice (9 a.m. and 6 p.m.) on daily basis on ratio of 3% of body weight of the fish.
(6) Thick plastic with measurement of 10 cm x 10 cm was added to the side of male fish.
(7) The pair of fish was conditioned for 15 days.
(8) Female fish was released to the male once the bubble nest size reaches 500 bubbles.
(9) Once spawning is done, the female is extracted out from the breeding tank.

During the incubation period, the temperature of the breeding tank is controlled with a digital thermometer (VIPRO) with a 0.1 Celsius minuteness. The temperature is set at 27 Celsius. 10 eggs were randomly selected from each breeding tank and were measured using a digital micrometer (Leitz, model 621).

Result
From the table below, it's shown that there is no significant differences (P >= 0.05) between different food treatments even though the pair fed with blood worms produced the most eggs and the lowest spawning time. (Note: Table below is not the best way to present your tabulated data).



Discussion
While the feeds doesn't show any significant impact in affecting the eggs production. As the brood stock is fed twice per days, if the feeding frequency increased to 4 times / day, will it impact the result? While live feed like Blood worms are rich with protein, does artificial feeds with similar protein percentage may have the similar or better results?

What you're going to do with the knowledge you've gained?
(1) Conditioning for 14 days or 2 weeks is crucial to make sure the pair of brood stock breed. Thus, we will need get a good partition to separate both fishes instead of using plastic container to hold the female Betta sp.

(2) Where can we get Gammarus?

What are the further unsolved questions?
(1) What is the optimum tank size suitable for breeding Betta sp.?
(2) What is the optimum feeding frequency suitable for the brood stock?

Note to Self:
(1) Be careful when selecting papers to read. Always check the references section to determine whether this is a significant paper to read.

(2) Paper with plenty of grammatical and spelling errors is a good indicator to skip it.

This Week I Learned 2019 - Week 11

Continue from last week or something before that.

What else I've learned this week not within this post? Still continue with the seventh week of ornamental fish culture learning. This week we looked into caring of your fishes in term of feeding and observation; siphon and larval removal. Also the start of discussion on larval rearing of Elacatinus figaro (Barber Goby) and Carassius auratus (Goldfish). The paper of the week is the Siamese fighting fish on the limited researches done scientifically. Concluding the week, HTTP::AnyUA is the Perl module we reviewed this week.

谁是你生命中最特殊的女朋友? 想不到,龙应台都已经67岁了。多年前,曾经读过的《野火集》。 如今,重想起来,仔细内容也不记得了,只有模糊糊的印象,还有少许的情绪。当然,毕竟都有些年纪了,也许是时候重温一下,再重新阅读这书。有些书,是要每年去重读一片,有些书,是要马上丢进垃圾桶。


What is something we usually do but still do it the wrong way? Taking medication at the right time. According to MyHealth portal, the right time to take your medication depends on the daily frequency as shown below. What's surprising that there are medication for 4 dosages per day. Must be quite a challenge to take those medications on time every 6 hours as we have to plan for meal time if the medication is only taken before or after meal.

(1) 1 dosage / day: 8 a.m.
(2) 2 dosages / day: 8 a.m. / 8 p.m.
(3) 3 dosages / day: 6 a.m. / 2 p.m. / 10 p.m.
(4) 4 dosages / day: 6 a.m. / 12 p.m. / 6 p.m. / 12 a.m.

According to MyHealth portal again, another misconception we have is taking medication before meal. It doesn't means that we should take it before we eat our meal. It should be taken 1 hour before meal or 2 hours after meal (Note: The 2 hours is something new). For some medication, 30 minutes before meal. To be on the safe side, 30 minutes before meal. So for medication to be taken before meal for 4 dosages per day, it should be taken at 5:30 a.m., 12 p.m., 5:30 p.m., and 11:30 p.m.

How about the 3 dosages per day? Why the third dosage need to be taken at 10 p.m.? For this schedule, the last dosage was scheduled at 10 p.m. because it's advisable to have a gap of 2 or 3 hours between meal and bedtime.

Again, consult your physician and don't simply read and trust any medical information found online.

Why this is the most strict feeding schedule for Betta sp.? Based on the baby betta care video of Big City Betta channel, we are surprised that the breeder (Amber) have such a strict feeding and water changes schedule (see screenshot below) for the first two weeks.


Compare to most breeders out there, her method in setting up the breeding environment is probably the most elaborate and humane. Typically you just get a container, add aged water and plants, condition the male and female pair, and release the female once the male have build a bubble nest.

Research Paper to Read: (2009) The Siamese fighting fish: Well-known generally but little-known scientifically

Source: Research Gate.

What are the key point here?
(1) There are 55 species of Bettas in Indochina and can be grouped into either nest building or mouth brooding care. Thailand have 10 wild Bettas where 4 are bubble-nest builders and 6 are mouth brooders. (Note: I'm quite surprised and thought TH have more, it seemed MY have even more wild Betta sp.)

(2) More research should be done locally but instead more publications are published by those living overseas with where Betta sp. is not abundance. (Note: Something similar to MY where most publications on Betta sp. came from SG researcher)

Why this paper?
As the common name implies, Siamese fighting fish, also known scientifically Betta sp. is a popular ornamental fish in Thailand. Ornamental fish is a large commercial fish export for Thailand especially Betta sp., which is the top two in term of revenues. There are numerous research paper conducted by Thai researchers to improve the production and conservation of this species. This paper focus on reviewing the general aspect of breeding Betta sp., newer scientific research on genetics of this species, conservation, and which areas should be prioritized by biologists and breeders.

Material and Methods
None.

Result
None.

Discussion
In Thailand, there are 10 wile Bettas types which are divided into two egg brooding cares of nest building and mouth brooding.

(a) Bubble-nest builder: B. splendens (Regan, 1910), B. smaragdina (Ladiges, 1972), B. imbellis (Ladiges, 1975), and B. sp. Mahachai (has not been classified)

(b) Mouth brooder: B. prima (Kottelat, 1994), B. simplex (Kottelat, 1994), B. pi (Tan, 1998), B. pallida (Schindler & Schmidt, 2004), B. apollon (Schindler & Schmidt, 2006), and B. ferox (Schindler & Schmidt, 2006).

The DNA sequence below illustrates the genetic difference of some of the Betta sp. and Gouramis (Tricopsis and Trichogaster).


The distribution of these wild Bettas as shown in both map below. Fishes are generally found in Paddy fields, marshes, ponds, lagoons, lakes, acidic swamps, streams, and brackish waters. While divulging exact locations may lead to poaching, the are several actual causes that endangered Betta sp. Urbanization, tourism, and agriculture are the main threats to the wild Betta sp. population.


What you're going to do with the knowledge you've gained?
(1) Atison Phumchoosri is a prominent world recognized Thai Betta sp. breeder which have been raising Betta sp. in a grand scale (20000 till 200000 fishes at a time) for many years. As a hobbyist, we don't breed in such scale, but his Thai breeding method is something we can learn from.

(2) Obtain other wild Bettas in MY and try to breed it and compare it with commercially breed Betta sp. and see what the differences. Try look for mouth brooder species.

(3) Investigate whether mangosteen (Garcinia mangostana) have effect on male/female ratio.

(4) Besides tropical almond leaf (Terminalia catappa), Yucca plant can be used in breeding tank to get rid of body water like ammonia. Both these plants extract is the active ingredients in Atison's Betta spa by Ocean Nutrition. Investigate on Yucca plant extract as a complementary ingredient when setting up a breeding environment.

(5) Look into publications and researches done by Horst Linke, the famous aquarist.

What are the further unsolved questions?
(1) Is there a distribution map of wild Bettas species in MY?

Research Paper to Read : (2017) Fruit Fly Maggots as Alternative Feed to Improve Siamese Fighting Fish (Betta splendens) Fecundity, Eggs Hatchability and Fry Survivability

Source: MyJurnal

What are the key point here?
(1) Fruit fly maggots can serve as alternative diet for Betta splendens in addition to bloodworms and formulated pellets which yields result with non-significant differences of average hatchability rate of 65% and survivability rate of 69%.
(2) Commercial pellets is not a suitable diet for broodstock for breeding purpose but it's good enought for daily diet consumption.

Why this paper?
It's rare to find local and recent research paper from local university from MY on Betta splendens. Furthermore, we are curious and researching about alternative diets in addition to existing typical diets like Artemia / Brine Shrimp, Moina, Daphnia, Vinegal eel, Blood worm, Tubifex worm, Mysis shrimp, Grindal worm, Flightless fruit flies, and beef heart. Even though, fruit fly maggots were not a common food source for Betta splendens, it's a common and popular live feed sold in aquarium shops here in MY as a live feed for large ornamental fishes like Arowana.

Material and Methods
This experiment uses 9 pairs (18 fishes) of Betta splendens of 4 till 8 weeks conditioned for a month (the broodstock should be around 8 till 16 weeks old). The fishes were fed with commercial pellets (there is no mention of the nutrients values of these pellets) twice daily during that month.

Experiments were done on three types of feed in 3 replicates:
(1) Commercial pellets x 3 pairs. Control group.
(2) Bloodworms x 3 pairs. Frozen bloodworms purchase from local pet shop.
(3) Fruit fly maggots x 3 pairs. Cultured using over-rippen banana left outdoor, eggs collected and hatched in container. Then the hatched maggots were collected and kept frozen in fridge.

The breeding conditions and procedure as follows:
(1) 1 or 2 days aged water with sea Indian Almond leaves.
(2) Male Betta was released first to build bubble nest.
(3) Female Betta was added but was separated in a separate transparent container.
(4) Female Betta was released once the bubble nest was constructed.
(5) Female was extracted once mating was done.

Result
The number of eggs produced by each diet is shown below. We're quite surprised that commercial pellet yielded a higher result than Blood worms. There is no mention of nutrients content of the commercial pellet so it's quite hard to deduce why commercial pellet is better than live food. Nevertheless, the broodstock with fruit fly maggot diet produced the highest number of eggs.

Discussion
The nutrients content of both live feed as follows:
(1) Blood worms: 52.8% of protein, 9.7% of fat, 0.38% of calcium and 0.90% of phosphorus.
(2) Fruit fly maggots: 40.3% of protein, 29.4% of fat, 0.59% of calcium and 2.30% of phosphorus.

The high fat and phosphorus may contribute to the high number of eggs spawned using fruit fly maggots as diet. However, there is no details on nutrient of the commercial pellet. Therefore, we can't reproduce this experiment and deduce that commercial pellet may not be a better choice than those two live feed.

What you're going to do with the knowledge you've gained?
(1) Learn how to culture fruit fly maggots to test the suitability of it as an alternative diet for Betta splendens for breeding purpose. Similarly, try with bloodworms as well.
(2) Check if we can breed the broodstock of age of 8 weeks or 2 months. Based on our observation, we don't think Betta fishes of 8 weeks have reach sexual maturity. 12 weeks or 3 months is considered just reaching adulthood.

What are the further unsolved questions?
(1) What are the dietary needs for broodstock to ensure fecundity (the ability to mass produce offspring) or reproductive performance?
(2) What are the feeding schedule in addition to the dietary in question (1)?
(3) As we have mentioned before, quite a few Betta splendens breeders sweared by Daphnia as its primary food source from larvae till adult. Comparison of diet should have includes Daphnia and Miona as well. What will be the expected results if both these two live diets were included?

Research Paper to Read: (2012) Effects of photoperiod on reproduction of Siamese fighting fish Betta splendens

Source: Research Gate.

Takeaways
(1) Photoperiod of ratio of 16h light : 8h darkness (spring) and 12h light : 12h darkness (summer) yield optimum reproduction and growth.

Why this paper?
As we have limited space, all our Betta sp. breeding projects were done within an indoor environment. For observation and appreciation purpose, the breeding and growing tanks were equipped with typical T5 LED lights. In the past, we kept the light on for 24 hours because we want to maintain the growth of the aquatic plants. Little we realized, it just dawned to us that animals and plants should follow the natural photoperiods just like in the wild. This begs the question, what is the optimum photoperiods when breeding and keeping Betta sp. Hence, the relevant of reading and understanding this paper.

Material and methods
This research includes 30 matured pairs or 60 fishes of super delta strain. On average, the weight and length of male is 1.92±0.28g and 3.84±0.13cm and female is females 3.72±0.18 cm and 1.72±0.23 g. (Note that the female size is roughly the same as male and typically for breeding, the female size should be smaller). These fishes were hosted within a 2 litres jar.

The design of the experiments for 5 treatments and 6 replicates for each pair of fishes as follows:
(1) 8L:16D
(2) 12L:12D
(3) 16L:8D
(4) 20L:4D
(5) 24L:0D

The breeding conditions for the next 150 days or 5 months are:
(1) Fluorescent light of 60 cm with 200 watt around 500-lux controlled by analogue timer.
(2) Total water changes every two days.
(3) Feeding done twice daily using diet of 45% crude protein and 12% fat in light photoperiod.
(4) Water treatment conditions are: pH 6.9±0.3, dissolved oxygen >5.0 mg L,-1 and ammonia <0.1 mg. L-1. Water parameters are monitored weekly.

Results
The graphs below shows that photoperiod of 16L:8D and 12L:12D shows the significant differences in frequency of spawn, eggs volumes, and fecundity. 24L:0D yields the worst performance of all the measurements.


Discussion
Does long exposure to light stresses the fishes which affects the production of the spawn size? The result indicates that this may be the main reason. Long light exposure is not natural and does not simulate a natural photoperiod (12L:12D) in outdoor or in the wild. Therefore, extra care needed to control the photoperiod as close as possible following the nature.

Further Questions
(1) Can we obtain similar result if the design and experiment was done in the outdoor environment where the photoperiod was controlled by exposure to sunlight?
(2) What kind of exposure to sunlight is suitable enough? The general consensus among breeder is that you cannot expose the fishes to direct sunlight but within the shaded area.

Research Paper to Read: (2016) Dietary crude protein levels for juvenile beta

Source: ResearchGate.

Takeaways
(1) The range of 30% till 33% crude protein (CP) level is the minimum acceptable level to ensure optimal growth and feeding efficiency for juvenile Betta fish.

Why this paper?
While breeding juvenile Betta fish, instead of live food, there are numerous formulated feeds in the market that we can use. Different brands have different formulation and CP level. What are the acceptable range of CP level to ensure optimal growth and reduce wastage?

Material and Methods
This experiment includes 192 juvenile Betta fish of 30 days age with initial average weight of 0.11 ± 0.02g. These fishes were grouped into 6 groups of CP level with 4 repetitions where each tank contains 8 fishes as shown below:

(1) 27% CP x4 repetitions
(2) 31% CP x4 repetitions
(3) 35% CP x4 repetitions
(4) 39% CP x4 repetitions
(5) 43% CP x4 repetitions
(6) 47% CP x4 repetitions

The breeding conditions for the next 30 days as follows:

(1) 6 litres tank with biological filter.
(2) Airting with temperature 26 ± 1°C.
(3) Feeding (done ad libitum) three times at 07:00, 13:00, and 17:00)
(4) Tank siphoned weekly. (Didn't mention percentages of water changes)

The diet was self-produced formulation feeds using the ingredients shown in table below. The feed was produced by fine grounding the ingredients and mix manually with water around temperature of 50 ± 5°C for starch gelatinisation. Pellets were produced using a meat grinder and dried using oven for 24 hours at 50°C.


Result
As the table below shown, CP of 31% and 35% have the highest weight gain and growth rate. Excess CP slow down growth due to extra energy need to catabolise additional protein and amino acids.


Discussion
Different fishes have different biological structure and diet needs. Hence, different fishes needs different CP levels. There was one master breeder which overfed the Betta fish to speed up the growth for competition. In his experience, overfed may also lead of loss of fishes as shown in previous table.

Further Questions
(1) What is the relationship between CP percentage and feeding frequency?
(2) What are the CP level needed for adult Betta fish or fry?

Research Paper to Read: (2004) Effect of feeding frequency on growth and fecundity in an ornamental fish, Betta splendens (Regan)

Source: ResearchGate.

Takeaways
(1) Two meals per day is the optimum frequency for growth, gonad (a testis or ovary) development, and fecundity (fertility on producing eggs).
(2) Don't overfed (three times per day) your female Bettas as it will increase it's mortality rate and reduce eggs production.
(3) 14 days is sufficient enough for subsequent spawn for a female Betta.

Why this paper?
One of the question when rearing and breeding Betta splendens is how frequent we should feed the fish to achieve optimum growth and speed up breeding. There are many inconsistent advice given by different breeders on the number of times the fish should be fed. Nevertheless, going through scientific literature will give us a baseline to feed our fishes at the optimum level without unnecessary food waste. However, this does not discounts the vast years of experience of master breeders as typical scientific research was done once compare to years of multiple trials and errors of some breeders.

Material and Methods
This experiment includes 375 juveniles Betta of 30 days old with weight of 0.045±0.01 g and lenght of 14.43±2.2 mm (not sure full length of just body only). The fishes were grouped into 15 groups of 25 each with three sets of each feeding frequency as shown below:

(1) One meal in three days (at 6:00).
(2) One meal in two days (at 6:00).
(3) One meal in one day (at 6:00).
(4) Two meals a day (6:00, 18:00).
(5) Three meals a day (6:00, 12:00, 18:00).

Breeding conditions for 77 days, roughly 2.5 months.

(1) 110-l circular cement cistern with measurement of 53.34 x 45.72 cm (the rounded container typically used by Thai Betta farm).
(2) 50l unchlorinated well fresh water. Tank were drained bi-weekly (didn't mentioned how much water)
(3) Temperature averaged 28±1C,
(4) pH 7.8±0.05.
(5) Water hardness 316±15 mg CaCO3/l, ammonia 1.01±0.12 mg/l and DO 4.04 ppm.
(6) Fresh minced beef liver (protein 35.44%, fat 3.86%, ash, 13.91%, and nitrogen free extract 46.79%)

Calculation of each type of measurements as follows:

(1) Growth. Calculation initial dry weight using electrical monopan balance. Five fishes were sacrificed (not sure how). Weight is determined every 14 days.
(2) Gonad. Calculation initial gonad weight using electrical monopan balance and gonadosomatic index (GSI). Three female fishes sacrificed (not sure how) every 14 days.
(3) Spawning. Upon attaining sexual maturity (did not mention when), two pairs of male and females where selected to spawn in a plastic container with water depth of 15cm. Eggs (hatched or unhatched) counted using sterilized needle.

Results
While the growth rate was expected for those with higher frequency feeding, there was no significant differences between two meals and three meals per day. Interestingly result of spawning size. As the result below shown, if the female Betta was overfeed (three meals per day), the eggs production will decrease. We're quite surprised that second and third spawn yields even more eggs after every 14 days.



Discussion
It seemed what we did with our breeding project was significantly not helpful to our female Bettas. To increase eggs productions, we've fed both male and female Bettas four meals per day. The result have shown that overfed actually decreased the eggs production and can cause bloating and dropsy. We've observed some of our female Bettas experienced such symptoms after mating.

Further Questions
(1) The paper did not address the impact of different meal plans for juveniles fish from 1st till 30th day. It only accounts for fish starting for 30 days old.
(2) Why not jar each juveniles fish and measure its growth, gonad development, and fecundity individually in separate container instead of one large 110-l circular cement cistern.
(3) To prevent bloating, some breeders skip Sunday meal so that the fish can fast to clear out all its waste. Will this have any significant differences to the result for those 3 meals per day?

Research Paper to Read: (2018) Minimal water volume for intensively producing male Siamese fighting fish (Betta splendens Regan, 1910)

Source: Research Gate.

Takeaways
(1) 150 mL water volume within 2 - 9 cm depth should be the minimum and optimum water volume to rear individual male Siamese fighting fish.
(2) Jar the fish when it reaches 1.5 months old (6 weeks) and sell it at 4 months old (16 weeks).

Why this paper?
Betta fish (B. splendens) is an aggressive and territorial tropical fish. To defend its territories, a Betta fish will flare its gill and spread its fins. Furthermore, it will bite its intruder. Therefore, upon reaching adulthood, the male Betta will need to be separated and jarred into separate and smaller container. However, a Betta fish spawn, on average, contains few hundreds of fries. Hence, to fully utilize available spaces and giving the Betta fish the optimum growing environment, what is the minimum water volume or container size that can achieve this? Our observation is most breeders will use several cost saving ways to jar individual male Betta fish. These consists of using recycle mineral water bottle, thin glass alcohol bottle, or drinking plastic bags.

Material and Methods
This is a randomized design experiment of 5 water treatments and 15 replicates. First, one-month old solid-red male Siamese fighting fishes were purchased and individually acclimatized in cylindrical plastic breakers (7.5cm diameter x 12.5cm height) of water volume of 250mL for 2 weeks (not sure why?). Then, 15 fishes (n = 15) of similar size (0.97 ± 0.01 g initial body weight)were evenly and individually distributed into 5 water volumes of 100, 150, 200, 250, and 300 mL glass aquaria (3.5cm width x 8cm length x 20cm height).

Breeding conditions for 8 weeks or 2 months as follows:
(1) Commercial floating pellets (10% moisture,  46% crude protein, 6% crude lipid, 5% crude,
fiber, and 12% crude ash).
(2) Feeding done twice daily (08:00h and 17:00h) at 2% of body weight.
(3) Photoperiod of 12h (light) : 12h (dark)
(4) Uneaten excess diet were siphoned after 30 minutes after feeding.
(5) 80% water changes with dechlorinated stock water within 3 consecutive days.

Since it's too long and quite complicated (I don't really understand it), I skipped the part on what measurements and tools used.

Results
Only the results for water quality and overall growth were discussed here.

Since leftover food were siphoned, the only contributing factor to water quality is the ammonia level due to excreted water by the fish. The lower the water volume, the higher concentration of ammonia level and lower pH level as shown in table below for water volume of 100mL.


Large water volume (300 mL) will lead to bigger fish growth (standard length) and at the same time, allows more space for increase movement (like bubble nest making) within the container, and thus, low weight gain.


Discussion
How big is 150mL? The video below will give you some idea. Should you use this minimum water volume for optimum growth? Depends. If you have large quantity of fishes, limited spaces, and plenty of time for water changes, then this should be the right option. If not, use the largest water volume possible so less than frequent water changes. When breeding and rearing Betta fishes, water changes is the only task that consumes most of your time.



Further Questions
(1) Will plastic bottle instead of glass aquaria have any significant effects on the experiment?
(2) When do we start to jar the male Betta fish? Is it 1.5 month of age when it starts to show aggression behaviour or when it reaches certain size of 2.5cm?
(3) Will there any significant changes if the water were treated with Indian Almond leaves?
(4) Is there any significant impact to the result if these fishes were fed with live food sources?
(5) Large water volume means less frequent water change. Is there any impacts on frequency of water change to the result?

Research Paper to Read: (2010) Growth and Survival of Siamese Fighting Fish, Betta Splendens, Larvae at Low Salinity and With Different Diets

Source: Research Gate.

Takeaways
(1) Combination of natural live foods (Chlorella sp., Rotifers, and Artemia nauplii) ensures good growth rate.
(2) Salinity of 5 ppt using non-iodized salt prevents the Piscinoodinium sp. parasite which is the causative agent of velvet rust disease.

Why this paper?
Betta fish (B. splendens) is one of the most popular ornamental fish and it's known to be easily breed. While there are numerous information (websites, books, and videos), most of these information are experiences gained through casual observation rather than scientific research. Two questions were raised during our breeding projects, how can we accelerate the growth and increase the survival rate of our Betta fish larvae (still have yolk-sac and unable to feed themselves) and later as fries (free swimming and can feed themselves)? This paper was written to answer both questions by investigating the best nutrients for the Betta larvae and fries for the first 15 days.

Materials and Methods
The larvaes and fry were the results of a pair of sexually mature (not sure how many months) B. splendens (not sure which species). The pair was fed twice daily (anytime) with flake food and live brine shrimp. Larvae were jararred at 3rd day into 18 round-bottom glass flasks (2L) where each flask contained 10 larvae. These were duplicated into 3 sets as follows:

(1) Treatment: Natural, Salinity: 0 ppt
(2) Treatment: Natural, Salinity: 5 ppt
(3) Treatment: AD + LA, Salinity: 0 ppt
(4) Treatment: AD + LA, Salinity: 5 ppt
(5) Treatment: SDLA + AD, Salinity: 0 ppt
(6) Treatment: SDLA + AD, Salinity: 5 ppt

Culture condition of the larvae as follows:

(1) Salinity was obtained by adding non-iodized cooking salt (aquarium salt should works as well) in portion of 5g/L in distilled water (all minerals were removed).
(2) Temperature set to 26C. (How do they maintain the temperature constantly?)
(3) Photoperiod, 12h light : 12h dark.
(4) 80% water changes on daily basis.

Below is the exact daily rations grouped into three stages of the larvae or fries lifecycle of 15 days. Larvae were fed four-times per day in a 4 hours intervals (0800, 1200, 1600, and 2000h).


Details of the diet with photos (from Wikipedia) as follows:

(1) Freshwater microalgae Chlorella sp.


(2) Rotifers (Brachionus rotundiformis, B. plicatilis "S type").


(3) Artemia nauplii (Brine Shrimp).


(4) Semi-purified microbound formulated diet (particle size 250–450 μm) with ingredients of (37.4% lipids, 46.2% crude protein and 5.6% ash)

Results
As the table below have shown, natural diet yielded the best survival rate and second in growth rate. The total average length of the fries is more precise to the observed and non scientific measurements of the Betta Growth Table.


Discussions
Why natural live food diet compare to formulated diet gave the optimum survival rate? Betta larvae or fries naturally eat moving living organisms instead of lifeless static food pellets. Furthermore, 100% survival rate was achieved with natural diet and non-iodined salt (5ppt salinity), which prevent the Piscinoodinium sp. parasite which is the causative agent of velvet rust disease as shown in figure below.


This is another photo (source: Wikipedia) showing the actual infection of the parasit.


I'm not sure why the diet of LA + AD with salinity cultured the largest growth length. Unfortunately, this was not discussed in the paper or did I miss or misunderstood it?

Further Questions
(1) When is the sexually mature age for both Betta male or female fish?
(2) How does the frequency of daily feeding (2, 3, or 4 times) influences the larvae and fries growth?
(3) How to calculate the salinity of 5ppt corresponds to the container size?
(4) How does photoperiod influence the growth, survival, or reproduction?
(5) How many percent of daily water changes needed?
(6) Why we need to perform daily water changes?
(7) Does distilled water essential for reproduction, growth, and survival of larvae or fries?
(8) Does the percentage of protein in formulated diet influences the growth and health?
(9) What is the range of salinity level for breeding Betta?

Betta Fish Growth Table

When breeding Betta fish, how do we know that the Betta fry is growing at the right rate? In the Interweb, most web sites will point to this growth chart of the Wayne's Betta pages. However, the measurement used in the page was not in metric system and it's always hard for us. Hence, we used the information from the page and converted it to metric system.

Note that this growth rate is based on normal Betta fish (Betta Splendens) and may not be suitable for Giant Betta which have different growth rate than normal Betta. Also we've extrapolated the growth rate for week 12.