Top Tips For Raising Big, Healthy Fish Fry | Part Two
I cannot stress the importance of water changes when keeping fish fry. From about day 5, I did daily 30 - 50% water changes on my fighter spawn tank, and from Week 2 I did 50% water changes twice a day. The result? At three weeks the bulk of the fighters are fully formed fish and some of them are even starting to show color. They have the size and appearance of much older fish, because frequent water changes not only keep the water clean, they also remove growth inhibiting hormone that make the fish grow slower.
As a new breeder, you will often be warned as to how delicate fry are, and told to be careful with water changes. This flies in the face of what everyone says about the importance of water changes, and leaves a lot of new breeders scared to do decent water changes. I found personally that about 4-5 days after hatching, fry were easily able to withstand 30% water changes, and I steadily increased these over time without noticing any ill effects.
Your mileage may vary of course, but the bottom line here is that you should not be shy about keeping the water in your fry tank clean. If toxins and hormones are allowed to build up in the water, you will have stunted, sickly fry guaranteed. A filter is no guarantee that the water is clean when it comes to fish fry. I have gotten away with not running any kind of filtration in my fighter fry tanks for the first month and my fry are robust. Why? Because I keep their water religiously clean. Water changes can take up to an hour a day, of course, but I feel it is worth it.
Food is incredibly important. Most breeders recommend live foods like baby brine shrimp and microworms. I followed their directions when I first started breeding and I found live foods to be an incredible pain in the rear end. Not only do you need several baby brine shrimp hatcheries going in order to ensure that the fish fry have a steady stream of food, but BBS can also cause swim bladder disorder, resulting in belly sliding fish that have to be culled.
Microworms were just as bad, the culture was easier to tend, but I found that many of my fish developed without ventral fins, a common problem when Microworms are fed.
I now use a reputable powdered fry food that you sprinkle a pinch or so on top of the water 2 -3 times a day. In spite of the dire warnings about fry refusing to eat food that isn't live and not doing as well on dry powdered food as live food, I've found the precise opposite. The fry I have raised in this fashion are far larger and more sturdy than previous spawns and they did not die off in large numbers from not being fed live foods, indeed, the die-off rate actually seems lower than usual. (In all spawns, a significant number of young will not make it to adulthood no matter what the breeder does. Fish spawn large numbers of young with the 'knowledge' (it's not really knowledge of course, rather a breeding strategy that has proved itself over millenia) that the bulk of fish will not make it to adulthood and will instead become prey for other fish, sometimes to the parents and other fry themselves.
Use a decent sized tank, don't be afraid of water changes and find a food that works for you. The needs of baby fish are fairly simple, but you have to be willing to put in the work that comes with them in order to get good results.