This post is the result of feedback I've received on my post about my 7G tank.
Could anyone kindly make a post about the typical 'good' fish for each of the following tanks based on size (including max fish for each tank).
7G
15G
30G
60G
120G
Thankyou very much...
I would say for a 7G you could have a nice school of neon tetras,
or a few platties/mollies/swordtails. Tetras get to be about 1.5 inches and the mollies/platties/swordtails get to be about 2 inches so in a 7G tank, if you want to loosely follow the 1" per gallon rule you are looking at 4-5 of the larger fish or mabye 6 of the tetras. Remember that your gravel and decorations remove from some of your usable gallons using this rule of thumb. Danios would also be a good choice. I just got some and they are wonderful fish!
15G I would say similar sized fish, but maybe twice as many. So maybe 8-10 of the 2" fish or 2 small schools of tetras (or one "big" school of 12 neon tetras). You could also have a school of 6-8 Cherry Barbs, or Green Tiger Barbs instead of the mollies. You could get a school of Congo tetras. I would stick to schooling fish over several individual fish because so many of the fish out there want to school, and if you have a small tank, individual fish will be more likely to be territorial than if you have the same species of fish together.
30G Still stay with small fish. 30G could house a single large fish but not much more than that. You might get away with one Oscar and one plecostomas. I would prefer to have several small fish. You could also forgo the small fish and get a few medium fish like Rainbow fish or Gouramis that get 5-6" long (so like 6 of them total).
60G I would say either 2-4 big fish (that get 10-12") or many small fish. For big fish you could consider an Oscar, Dempsey's or Tin Foil Barbs. My parents have had all of these fish at some point since I was little and they are neat fish. Dempsey's are aggressive fish though, and should be housed with bigger fish (like 1 Oscar and 1-2 Dempsey's). You could have a bigger sized plecostomas with big fish (as one of your 2-4 fish). Common Plecostomas's can get very large so try to find a species that only gets 10-12 inches at adult hood.
120G I don't know a lot about big fish. I suspect you could put a small species of "shark" (they aren't real sharks but they are called sharks because of their shape) or several big fish like 5-7 big ciclids (like Dempseys), or you could make a beautiful Discus tank with some large Discus. I didn't say Discus or Anglefish before now because many of them get very tall and the 120G is likely to be taller than some of the small sizes you mentioned.
Find out about the fish that you are interested in first and find out what temperature, pH, hardness and so on they like. You may find that some of the fish you want to get would not be compatable because of water conditions before you even check to see if they will fight with eachother.
You may also find that all the fish you like want to live at the top level of the water, and that will make them feel more crowded and upset than if you had some fish that stay towards the bottom and some that stay towards the middle or top.
I just got some little danios and they love to stay near the top of the water. My male beta swims at all levels of the tank, and my checkered barbs like to stay near the bottom of the tank.
Maybe if you tell us what fish you really like, we can recommend some tank-mates and tell you how much space you will need for the ones you like. That is a good way to start if you are flexible with your aquarium but have some definate likes in terms of fish.
You should start with one thing for sure, either the tank, or the type of fish. Then build everything else around that. (for example if you already have a 60G tank we can tell you some things to go in it. If you have no tank, but really want to have Spotted Goby's we can recomnend the right size tank and some tank-mates that will get along)
-Nerwign
