Mixed Growth rate from same spawn

[mostlydave]

My latest spawn of about 15 CPD seem to be growing at different rates. Is this normal, will the little ones catch up? The largest fish in the batch is a little over a half inch and the smallest looks less than half it’s size, with the other fish everywhere in between. Anyone else experience this? Is there somthing I’m doing wrong or anything I can do to ensure more uniform growth?

[BallAquatics]

I would recommend more water changes. After my fry are about a week old, I do large 80%-90% water changes daily. The larger fish will put out a growth inhibiting hormone to keep their smaller siblings from growing. The large and frequent water changes prevent the hormone from having any affect. When growing out fry, high quality water is every bit as important as high quality food.

Dennis

[mostlydave]

I’ll be doing the 80%-90% water changes on my newest batch of fry which are just hatching this week!

Do you have more uniform growth in your batches?

I usually keep my fry in a 5/12 gallon tank for the first month, do you keep up the daily water changes for a month? after that I move them to a grow out tank (20 Gallon) that gets weekly water changes, I only had about 20 fry in my last batch.

[BallAquatics]

@mostlydave wrote:

Do you have more uniform growth in your batches?

Yes. The fish are all more or less the same size. At some point after 8 weeks, the females seem to grow just a bit faster than the males. It may just be that as they reach sexual maturity the fatten up so to speak. This may have the effect of making them appear to grow a bit faster?

@mostlydave wrote:

…do you keep up the daily water changes for a month?

After about the first week I do. For the first week or so, I don’t do any water changes, but after that I start. It’s easy enough to do changes on 5.5 gallon tanks and the results speak for themselves. Give it a try and see what you think.

Dennis

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