Fry feeding confusion

[Beastije]

Hi. Last week monday I noticed in my separate tank, 54liters, that houses 13 rabbit snails (3 adults, rest babies), my white cloud minnows spawned. I moved them there the week before and after three days removed them, so it was expected.
However. I feed several times a day, some hikari first bites to stick on the surface, I did "hatch" protogen in a different container, it is supposed to include rotifers and infusoria so I would take the cloudy water and pipette put it in "fry" tank. I also have microworms, so I slowly add some of those to the tank as well.
There were only four fry, there are still four a week later, but the growth rate seems very slow to me. Yes there was a big bump between the first day I noticed them and now, but not as large as I expected for "fish that grows before your eyes".

I cant tell if they eat the microworms at all, because once I put them in the tank I cant see them (the worms) and yes, the fry hang around the place I fed but I dont notice the actual consumption. Biggest feeding "success" based on the size of the stomach is the dried food, but I read you cant raise quality fish just on dry food.
I fed hatched bbs once last week and once today. Last week the fry was about as large as the bbs. Do I have some wrong bbs? Are there different sizes? Everyone says how freshly hatched bbs is a perfect food for fry, how they should be able to accept it, but it is just too large. Today feeding two or maybe three fry have orange in their bellies, so I assume they managed to eat some, but the rest are just sort of hanging around, no orange bellies and they are a tad smaller than the other fry, which could explain the issue with them not being able to eat it yet.

Ofcourse the tank is large for just 4 fry, I expected a higher yield, and they hang around the surface areas, but both microworms and bbs tend to slowly fall down to the substrate (where they will be eaten by the snails, so I am not worried about contamination of the water), so that could be the reason
Or, given I have no previous breeding experience like this, it could be the fry are doing ok and I am just too worried.

Do you turn off the sponge filter during the feedings?
Any tips for me please? Thanks

 

[Colin_T]

Fry don't grow much during the first few weeks. It's not until they get onto newly hatched brineshrimp that you see some major growth.

When feeding green water and infusoria, you need the water in the rearing tank to be green in colour. There should be lots of infusoria too, so the fry can literally just turn and grab, turn and grab. They shouldn't have to swim across the entire tank to find one bit of food.

When you get them onto newly hatched brineshrimp and other foods, you feed them 3-5 times a day and give them enough food so they are fat like a pregnant guppy. Then add some more newly hatched brineshrimp so they can pick at them over the next few hours.

When they are all eating newly hatched brineshrimp, start doing daily water changes and gravel cleans to keep the tank clean. Make sure the new water has the same temperature and water chemistry as the rearing tank, and make sure it is free of chlorine/ chloramine. I used water from the adult's holding tank to do water changes on the rearing tanks during the first few weeks. When the fry are silversides (move down into the middle of the water column and develop silvery sides), then you can use tap water that has the same temp as the rearing tank.

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Baby fish come in different sizes and newborn livebearers can be fed on newly hatched brineshrimp and microworms from day one. However, most egg layers (including White Cloud Mountain minnows) have much smaller fry and these need green water, infusoria, or very finely powdered foods. After a week or two you can start adding newly hatched brineshrimp and offer that to them each day. When all the fry have fat orange bellies, you can stop feeding green water and infusoria, and just feed them brineshrimp nauplii. After a week or two on brineshrimp nauplii, you add microworms to their diet so they get worms and shrimp larvae. After a couple of weeks on these food you add crumbled up dry foods and very finely chopped prawn or fish (marine mix is good and a pr of scissors works well to cut it into tiny bits). Then you keep them on this diet until they are adults.

The low number of fry is probably due to the snails in the tank. They eat fish eggs.

When you first remove the adult fish from a breeding tank, you should reduce the water level to about 5-6 inches. This means there is less water for the fry and that means they will be closer to any food you add to the tank. If you have a really full tank and newly hatched fry, the baby fish will quite often struggle to find food. Having less water means the food and fry are closer together so they have less issues finding food, and use less energy to get to the food.

Air operated sponge filters should be run continuously. You don't need a lot of bubbles when the fry are young but they need some water movement to help circulate the food around the tank.

Newly hatched brineshrimp will live in fresh water for several hours and the fry can pick at them during that time.

 

[Beastije]

Thanks for the reply, I basically ended up doing what you advised.
I fed several times a day, first two weeks the protogen culture water and hikari first bites, then I started adding microworms and freshly hatched bbs, supplementing still with first bites and sera vipan baby fry food. Within four weeks the largest of the fry reached 1/3 of the parents sized and was moved to the adult tank.
They even survived my 5 day vacation in week 3, when I had someone here put in a measured spoon of first bites into the tank on day 2. Granted the tank is large for them, established, full of plants, leaves and rabbit snails that with their poop could produce something for the fry to eat.
I cant wait for next attempt, but I will be gone a week in august so I better start after I am back

 

[TwoTankAmin]

When hatching and feeding BBS it is important to understand that they must be fed very soon after they hatch or they will have little or no nutritional value. And if one keeps the BBS alive for any time they need to be fed to raise their nutritional value before they are served to one's fish.

Here is a pretty good article on hatching and feeding BBS and adult brine. It was written for reef keepers but almost all of it ap[plies to FW as well. The one difference is SW fish need the brine to be fed a special enrichment not needed by FW fish. Aside from this everything is pretty much the same for FW or SW fish being fed brine.

Have a read here, it is well worth your time https://reefs.com/magazine/aquarium...ive-foods-for-the-coral-reef-aquarium-part-2/ After reading the article I corresponded with Dr. Toonen for a while on the topic of feeding live foods and their nutritional value. That was about 18 years ago.

I messed around a bit with hatching BBS and fave it up. I understand live foods are normally beast for fish, but they are more than I can or am willing to do. So I use frozen as the next best alternative. I feed my fry a mix of frozen cyclops, rotifers and a bit of daphnia. The daphnia is for the somewhat older fry which can eat them but not for the smallest of the fry. I normally have fry in breeding tanks and that also means I have more mature kids as well.

 

[Beastije]

When hatching and feeding BBS it is important to understand that they must be fed very soon after they hatch or they will have little or no nutritional value. And if one keeps the BBS alive for any time they need to be fed to raise their nutritional value before they are served to one's fish.

Here is a pretty good article on hatching and feeding BBS and adult brine. It was written for reef keepers but almost all of it ap[plies to FW as well. The one difference is SW fish need the brine to be fed a special enrichment not needed by FW fish. Aside from this everything is pretty much the same for FW or SW fish being fed brine.

Have a read here, it is well worth your time https://reefs.com/magazine/aquarium...ive-foods-for-the-coral-reef-aquarium-part-2/ After reading the article I corresponded with Dr. Toonen for a while on the topic of feeding live foods and their nutritional value. That was about 18 years ago.

I messed around a bit with hatching BBS and fave it up. I understand live foods are normally beast for fish, but they are more than I can or am willing to do. So I use frozen as the next best alternative. I feed my fry a mix of frozen cyclops, rotifers and a bit of daphnia. The daphnia is for the somewhat older fry which can eat them but not for the smallest of the fry. I normally have fry in breeding tanks and that also means I have more mature kids as well.

Thank you! it was an interesting read. I feel like I should be ok, because I always feed within 8 hours of hatching, so they should never reach an instar ii stage.
But the inefficiency of feeding with just bbs or microworms is understood, that is why I always supplement with power food, for the vitamins and minerals content. I even switch brands to ensure some sort of variety