somethings gonna eat that frog, and that rainbow sharks gonna start getting fiesty with someone, if it's the pleco then when they mature there could be war! ...
Overstocked tank, 3 things could happen. You fish die of stress, You stunt the growth of your fish and they die prematurely, your fish still grow and end up not being able to turn around in a tank that small.
If it sounds like me or rayneuki are being mean, WE ARE! Wherever you got advice from for setting up and stocking your tank, it was bad advice and it may not have been your fault. What we can do though is help you set up the right tank for your fish so they will live happily and grow, otherwise you can return them to the fishstore (you should be able to get store credit or exchange them for fish that stay small) Or you could let them suffer and die in your tank.
The catfish requires a 20G tank
The rainbow shark is territorial and requires a 30G tank minimum with hiding places and NO OTHER SHARKS ALLOWED TO BE MIXED.
The pleco, if common can grow to be near 2 feet long. It needs a 75G tank.
The African Dwarf frog is the only species you have that can suitably live in your tank.
Fish need tank space because they need room to swim, and excrete wastes without having to breathe it right back in. Also some fish like your rainbow shark are territorial and need their own area to defend.
5 gallon tanks aren't meant to hold much. You can have 3-4 dwarf frogs in there, or 1 betta fish. It's too small to keep schools of fish or fish that grow > 4 inches.
I recommend returning your fish, get a few more dwarf frogs and just keep them in there.
***Don't take offense to this post, this is constructive criticism. See new post ***