I have a 10 gal tank?

A small dog or cat for a tank???? Lol

Anyways, if you want a hardy fish don't go with a goldfish, maybe a betta along with an African dwarf frog :) you can be creative with hiding spots for the frog and everything if you wanted.

Or, you could get a gecko. You will need a cover for the tank, a heating lamp/pad, some plants that stick to the side of the tank, logs, rocks... It's really up to you. Geckos are cool, rarely are they mean (leopard geckos, gargoyle, etc). Only one I won't recommend is the "tokay" (the name of the mysteriously appearing meany I found while cleaning anplated lizard tank escapes me) gecko... You have to dunk them in water to get them to let go (toothless, but with a strong grasp that sounds similar to snapping fingers or clapping hands lightly when it snaps it's mouth).

They'll eat crickets.

ok, first problem is you got hamsters - not the best critter pets....second problem - you got 2 hamsters, you only should have gotten one otherwise fighting is inevitable. Honestly, I would recommend getting a rat...I know a lot of people think they are gross or whatever but they are actually very sweet, affectionate critters. I've had rats for years - they come up to greet you, enjoy being held, lick your fingers, you can train them and teach them tricks, I would let mine run around and they would come when I called them and jump up on the couch with me, not nippy at all - I have never been bitten by any of my rats. They are really great pets and very misunderstood - I would read some info online about them - I highly recommend.

In my 10 gallon tank I had a Syrian hamster. It's no fish but she was adorable. She died of wettail though. Look up some information on hamsters.

get a hermit crab for each of your kids they are great pets and easy to take care of and they dont pinch usually

don't get a lizard or a bird because its too cruel get something like a small dog or cat or sea monkeys

tadpoles are good too