The only huge difference is that in a fish tank the gerbil wont flick things out through the bars, and in a tank your gerbils will also be tame faster as they have no place to hide. but a cage could be more fun for a gebil if it has lots of levels, ladders and platforms - but you could always add these to a tank with a bit of difficulty.
a small cage, like a plastic fish tank with rocks
Gerbils are not fish! They do not have gills and such.... they are rodents... I have one of my own!
Rodent.
fish, bird, hamster, housefly, turtle, and gerbil
No, most definitely not! Hamsters (at least Syrians) don't even get along with other hamsters, much less another species. Fights will break out. In general, unless you have a very large enclosure (like in a zoo), you should never mix species, except for fish and some kinds of amphibians and reptiles.
if you have your fish in a cage the water has probably drained out and he is deceased, you must always put fish in an aquarium
yes
To clarify. when you buy a fish it is put in a bag. When you get an amphibian you get a little cup/tub. What do they provide when you get a pet bird? or should I buy a smaller cage for transport?
placing a huge cage in open sea and let the fish grow inside the cage naturally
Hamster , Guinea pig or Gerbil .
have a crayfish cage in your inventory and fish at a cage fishing spot
have a crayfish cage in your inventory and fish at a cage fishing spot