Hey guys, I'm new to this forum!
I had a 60litre tank for a while and have recently upgraded to a 240litres (55gal) tropical set up. Up until a few weeks ago I had 7 small angelfish, 3 small silver sharks, 6 small corys, 10 penguin tetras, 1 medium sized plec apple snails, bamboo shrimp, cherry shrimp and a couple or red tropical crabs. I then bought 3 large gouramis, a small plec and 4 paradise fish.....is my tank overstocked?
Yes, there are a few issues:
1) Angels - how tall is the tank? And 7 is a LOT. When these guys are all grown up (so 6 inches x 8 inches) you are going to have fun fitting them in with all the other fish. The kind of fun that isn't actually fun.
2) Silver sharks AKA bala sharks. These guys grow to a foot long and need 6 foot (minimum) tanks.
3) Plecs . . . what kind? Common? Sailfin? Gibbiceps? Bristlenose? Some plecs would be absolutely fine in your tank. However, if you paid under £4 for a small one . . . it'll probably be a common or sailfin, and these guys can get to 2 foot long. Another addition to the 6 foot tank.
4) Gouramis - again, what kind? Some will be fine. Many will be fine . . . some (like giant gouramis and kissing gouramis) will need a much larger tank. If they are giants (and I hope not), then rehome them. Even the 6 foot tank isn't big enough. If kissing or another species that sits in the 10-12 inch bracket, then they'll do very well in that 6 foot tank.
5) Crabs - don't be surprised if some of your fish are injured or eaten. Really don't recommend keeping them with fish. Also - will need some dry land.
6) Paradise fish - these guys prefer 22-24 C so you may find need a rather cooler tank than the one you have.
All fish grow up. It is very rare for the shop to sell only adult fish and it is also very rare for a shop to only sell fish into the right tank or to even know how big all their stock will get. You seem to have fallen into the trap of liking the look of a fish and so buying it. There will always be a way to get the fish you want to research before you buy.
Never think about whether you are overstocked now, as that can lead to a false sense of security. When you realise you have several 20 cm long fish that may have stunted growth, suddenly it becomes very urgent to rehome them but what happens if you can't? Or what happens if you decide to upgrade the tank "in a couple of years" but can't afford to or need to move to a smaller house?
What about this for a stocking plan:
3 x angels
6 x corys (are they all the same species?)
10 x penguin tetras
1-2 x apple snails
4-6 x bamboo shrimp
6-10 x cherry shrimp
3 x gouramis (assuming they are not species that exceed about 5 inches)
Then you could add:
1 x bristlenose or bulldog plec
10 x other tetras/rasboras OR 7 x tiger barbs (or similar)
But wait until everyone has settled down and grown a bit first. You won't know how your tank is doing and whether it can cope with more fish unless you give it time.