Aradiane
The fish that are caught in the minigame and the fish for the aquarium are seperate types of fish.
Both features are pretty much 'dead in the water' too, so gaia isn't going to update them unless they can see some way to milk us out of more money for it.
If you want fish for the aquarium, try dumpster diving. I get a few fish every now and then there.
Gaia really shouldn't touch fishing anymore...even if it stayed free I don't really have the confidence in them to not mess it up. Plus fishing is the only real way to make gold if you're even halfway new (practice in bas'sken and gambino until you can fish durem and catch some boldurs for a couple mil each [I know mils aren't barely anything anymore but much better than the thousands you get for any other minigame and if you don't have the gold to vend you have to get it somewhere] )