Sinking ACF

[emberlisa]

Hi. I've taken some photos for you guys to look at. I apologize for the poor quality, they were taken with my cell.

Here are pictures of the ones that stay along the bottom:



And here are photos of the siblings, which are kept in the tank with the light and filter:


Is it to early to tell the sex?

I agree with the above comments. Could you post a photo of the feet that you're worried about? I'd say there is definitely a chance that your slower froglets are just that: "slow". Some frogs just tend to be lazy or are "special", but I'm still betting on it being an environmental thing. Is there a reason you have them in separate tanks to begin with? Have these guys always been much smaller? Pics comparing the slow guys to the regular guys would be really helpful.
I wouldn't worry about them eating only sunken food. Frogs get used to obtaining their food a certain way. If they are used to finding it on the floor they aren't going to look for it at the surface. As long as they still have a good appetite I wouldn't worry about it. Are you only feeding them reptomin? Because nutritionally that could be part of the issue.