Baby fish... how soon can you tell the species?

If you feed them often and do daily water changes, they grow quite quickly. In the main tank, it's going to be a different story altogether. They won't be able to eat as much or as freely as they would in a fry grow out tank.

It may be sometime before you can determine what species it is.

They aren't going to exhibit the same behaviour in the main tank as they would in a tank full of fish there own size. Stress will cause them to "colour" down, as will the slower growth rate.

so, if this fish is a cm long..... do you think its from this batch of fish? or a lone survivor from a spawn like 2 mos ago? i cant imagine that i wouldnt be seeing it until now ya know? i am always looking in there for babies it didnt appear until the other day after the two spit

It's hard to say which spawn it came from. It could easily be your earlier spawn, but on the other hand, I've had fry spit that were a cm in length!

It's a mystery fish!

cool! i am sure it was from the yellow lab... it didnt appear till after she spit and since she held 6 weeks its very possible that its 1cm long!!!!!! i wonder how many she had in there and if there are other survivors! thats the mystery!