It sounds like you are sexing the fry by looking at the males. The females will show you their gravid spot sooner. Some people like to look at them that way so some females can be removed and raised on their own. That way, when that little, short-finned, runt male shows himself. He will not have inseminated all of the females. ;)

DJ, it sounds like your leak is in the tank bottom. Be very careful. If you have to remove a significant amount of sealant, you may want to either use masking tape or even duct tape to hold the tank together so there is no slippage (which is bad for the tank, dangerous for you.) Don't completely disassemble the tank. That is a whole lot bigger project and you probably would need a frame to hold the sections together.!

When you have cut out what you needed to cut, vacuum the debris out. Wipe with alcohol. (How does one keep their head out of a 55 while wiping it down with alcohol?)

I noticed on a cichlid site someone suggesting a steel wool stage before using the alcohol. I don't know. If you do, be gentle and vacuum again after that.

I have a question as to how far one has to cut out sealant. I have an e-mail to my informant now asking his advice on this. I'm sure you wouldn't mind knowing, perhaps as soon as tomorrow. I'll try to call him in the morning if I don't get a return e-mail.