After a week 1 tetra still is agressive - What to do?

That is not true. Look up stunting. That is what is happening. Fish do not grow to fit their environment. They stop growing externally, but inside, their organs are still growing, crushing them from the inside when they don't have enough space. Keeping a fish in a tank that does not allow them room to grow to full length is tortuous to the animal.

Whoa whoa WHOA.

This bala guy was dead on when he said that balas will only grow to the size of their tank. Their skeletons will, their organs will not. In essence, they get crushed to death from the inside out by a condition caused by stunting called organ compaction. Why do you think he keeps his balas in a POND?!

Also, what exactly defines the size of the tank. Just because their growth will be stunted does not mean they can't still grow larger than what your tank will support. In fact, skittish balas (from being kept in inadequate schools) have been known to bolt into tank walls and the lid when they get startled, potentially breaking the tank.

Furthermore the bioload of even 2 balas and a pleco alone will be too heavy for your tank, stunting or no, poisoning your fish with ammonia, nitrite and nitrate (ie their own waste).


As for the tetras, 6 is the minimum they can properly be kept in, but a school of more is way more likely to work out successfully in your tank.

Jeesh, thanks for making me feel like I am killing them :( I mine as well bring everyone back and just put the tank away at this point :(

Were not trying to be mean to you, but we are letting you know, it is killing them. There's no need to ditch the tank. There PLENTY of species that can adequately live in a 30 gallon tank. Just do a bit more research! ;)

Yeah pet stores are the master of misinformation and we know you have good intentions but that doesn't mean it's right to keep these fish in an improper tank.

A LOT of people come to this forum after stocking a new tank then realise 'Oh shoot..." and wind up taking half their fish back to the store. It's not uncommon, it's all part of the learning curve and it's a hard lesson to learn that pet stores are only out for your money.

All you have to do is take the plec and balas back (perhaps give the balas to your friend's pond?) and you will be fine.

The fish store here is actually a family owned store and they are real knowledgeable with fish. They'll tell you the truth. Which is weird compared to other "petco's" where they are just interested in money. The pleco I got from a friend who works there, the pleco is about 2 years old now, the first year the pleco was in a 10g tank. The bala sharks can't get any bigger then they are now. They're already 5-6 inches in length. Can't see them getting bigger.

This is a Bala Shark a guy is trying to sell on the classifieds of my local forum. 3 years old. He thought the same thing as you did. Now the fish is 13"... the fish behind it is a Kissing Gourami, which is about 5".

Even independent fish stores have a reputation for questionable advice. I am still wary of some of the advice I get from LFSes I know to be correct most of the time. Some of them are great and know a lot about fish, but when it comes to stocking and adult size the vast majority of corporate and independent pet stores fall short.

Wow I never knew the organ/skeleton growth thing...

Anyways, apparently they aren't very knowledgeable with fish if they are giving misinformation. :p

Those particular fish may not be suitable for your tank, but that doesn't mean you should pack it up and get rid of it. There's plenty of fish who will work just fine in your 30g aquarium. That don't get to be too big for it.

With tetras and many "nippy" fish the best control mechanism is more of them. What you're seeing is perfectly normal behavior for the fish but the difference is that they're in a drastically smaller group than they are in the wild. What happens is the nipped fish can't get away from its aggressor and get lost in the "school". In some ways you have to treat nippy tetras like you would cichlids. Simply get enough of them that no one gets picked on excessively.