Showing posts with label goldfish. Show all posts
Showing posts with label goldfish. Show all posts

UMT MOOC: Ornamental Fish Culture - Topic 7: Seed Production - Larval Rearing - Carassius auratus, Goldfish

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Carassius auratus or commonly known as Goldfish is one of the most popular ornamental fish in the world. We have discuss about the quality characteristics and numerous species. As with most fishes, feeding should be done in delicate manner in larvae stage as fishes at the stage are too fragile and sensitive to sunlight.

Goldfish have preference for live feed for all stages of its life cycle. Artemia nauplii or Brine Shrimp is suitable for fry and Mosquito larvae, for fingerling, juvenile, and adult. For best optimal growth, for the first 14 days, feed with Artemia nauplii. For the next 14 - 21 days, feed with a mix of Artermina nauplii and dry feed (Source: Comparison of the nutritional status of goldfish (Carassius auratus) larvae fed with live, mixed or dry diet). When the fish reach juvenile or adulthood stage, 21 days after post-hatching, live feed as such Mosquito larvae is economically cheaper and suitable due to its high protein content.


For feeding frequency, twice per day is optimal for body weight gain (Source: Influence of Feeding Frequency on Growth performance and Body Indices of Goldfish (Carrassius auratus)).

UMT MOOC: Ornamental Fish Culture - Topic 3: Quality Characteristic Determination - Koi & Discus

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This post will delve into the acceptable standards for quality Koi and Discus fish. As I mentioned in my previous posts before, the beauty is in the eye of the beholder. If you're a hobbyist, the first question you should ask yourself. Do you like the fish? Are you excited? If so, regardless the standards, go for what you like. A fish personalities or deportments is hard to gauge and subjective by person to person. Nevertheless, let's continue with our discussions.

Koi fish. Due to enormous varieties and rivalry between breeders around the world, it's quite hard to finalize on which is the best koi. However, there are some guidelines on quality koi which can be summarized into four characteristics: (1) Size where shape, volumes as well as fins are symmetry,  (2) Colours should be deep, intense, and uniform, (3) Patterns should be uniform, scale should be sharp, and not dirty marks, and (4) Presence as in personality and vitality.

The video below should gives us some clues on top notch quality Koi.


Discus fish or I like to call it pancake fish. It seemed we still don't have a good published standard even though there were many competitions held? The general consensus rules for good quality Discus are: (1) Overall impression, the wow factor. (2) Size of the fish on its proportion, the body shape is round and high, (2) Fins are long and extended, symmetry, and good proportion to the body (3) Colours are vivid and unique clear pattern and (4) Eyes size and colour as well as the proportion to the body size, and (4) Swimming pattern is steady. Below is the video on how juries judge Discus fish.


Examples are the show grade Discus at 2nd European Discus Championship as shown in video below.





UMT MOOC: Ornamental Fish Culture - Topic 3: Quality Characteristic Determination - Goldfish

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As mentioned in previous post, standard for any fish species serves two main purposes. First, it's used as guidelines for any competitions. Second, it guides breeder to select the best pair of fishes with desired characteristics for breeding project. For Goldfish, there exists three competing or complementary standards (there should be more from China and Japan):

(1) American Goldfish Association (AGA) Goldfish Standards, Revised 2009.
(2) Nationwide Goldfish Societies UK, Revised 2016.
(3) Federation of British Aquatic Societies (FBAS), Eleventh Edition, 2002.

Something about breeders, competitions, and standards. Breeders are the most passionate type of people around and there are always conflicts and politics on standards. Case in point, the incident that leads to the two standards existed in UK.

To identify good quality Goldfish, first we need to understand the anatomy of this species as shown in picture below (Source: AGA Goldfish Standards, 2009). First morphology is different from species, Goldfish is definitely have more mutations than other ornamental fishes. The Goldfish varieties is determined by three characteristics of existence of dorsal fin, tail type, and special growth.


According to Nationwide Goldfish Societies UK's judging standard, points are given based on these five categories of body, colour, finnage, special characteristics, and condition and deportment. The last category (deportment) required special training from breeder, where how the fish swim and react to external stimuli.