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?

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