I aslo think what you have is a common plec but you may want to post that pic in the catfish section - you'll probably get more deffinitive answers there.
As for growth - they'll grow healthily and quickly if you give them a good-sized tank but they'll grow slower and usualy also be far more likely to fall ill if you compromise their space. I'd strongly urge you to re-home this fish while you still can as you may well find, a year or so down the line, that you can't find a new tank or are not ready for one - and then you'll likely find you can't re-home the plec either because it's too big.
Note also, that as this fish matures, you'll start finding long trails of poo strung all voer your tank's decor. That's not an exaggeration - they produce a ridiculous amount of waste - probably enough for a fish 4 times their size
My point is, with a large plec, you also risk over-stocking or making more work for yourself (in the form of water changes and disease treatments).
As for growth - they'll grow healthily and quickly if you give them a good-sized tank but they'll grow slower and usualy also be far more likely to fall ill if you compromise their space. I'd strongly urge you to re-home this fish while you still can as you may well find, a year or so down the line, that you can't find a new tank or are not ready for one - and then you'll likely find you can't re-home the plec either because it's too big.
Note also, that as this fish matures, you'll start finding long trails of poo strung all voer your tank's decor. That's not an exaggeration - they produce a ridiculous amount of waste - probably enough for a fish 4 times their size
My point is, with a large plec, you also risk over-stocking or making more work for yourself (in the form of water changes and disease treatments).
