Big, 12 inches, only because it would be nice if the fish could swim from end to end and turn around in the tank.
About the biggest fish I would put in a 30-gallon aquarium is a firemouth, which gets to about 5 inches long.
The usual calculation is 2.5cm of fish requires 4.5ltrs of water. Do the sums but don't foget that the tank will hold considerably less than it's stated capacity once substrate and landscaping is done and you take into account that the water never goes up to the brim. Your tank will probably only contain around 22ltrs so you would be looking at around 12cm of fish in total length. If you add efficient filtration and air you can double the holding capacity.
any type im sure , it has no range. I dont think:) When it's set up properly with substrate, plants, filter, heater, thermometer, cover glass and lights, the tank will only hold about 25 gallons max. So I would be looking at smaller species like Tetras, Barbs, (small) Danios, Dwarf Cichlids, small livebearers etc. Just remember to use the 1 inch of fish per gallon of water rule.
I would recommend the following:
1x Siamese Fighting Fish
-or-
x6 Neon Tetras/Zebra Danios/White Clouds
-or-
Fill it up with live plants and add some cherry shrimps.
Fish that eat each other are less compatible than those who do not.
If you mean goldfish than you could comfortably put 2 goldfish in a 32 gallon tank.
Guppies are usually 1 inch long, and a good rule of thumb is to have 1 inch of fish per gallon, so as many as 30 guppies will be just fine. Although, it might be nice to add some different fish occasionally.
Pirrahna.
30 gallon
Exactly 30 US gallon.
No it will get too big
Goldfish grow extremely large; fancies will become fatter, and singletails grow quite long. You should only have 2 fancies in a 30 gallon, or one singletail for proper health and growth.
The rule of thumb is 1 gallon per 1 inch of fish. But of course if you have bigger goldfish you will need more room. So for larger fish, go 1 gallon per 3 inches of fish.
Get 30% off Big Fish Games.
At a Petsmart, Petco, aquarium builder, or a trusted pet shop
No matter what its dimensions are it is way too small to keep most fish in successfully.
No! It's not big enough you need a 10 gallon to 20 gallon tank or aquairuim for breeding and you need to be experienced for breeding. In short, no you can't try a 10 gallon tank or over that :) hope I helped
I would say a lot of little fish like tetras :)