They are against a hobby that its destroying the natural ecosystem.
Then they need to buy a clue - the fish keeping hobby is not destroying more than a tiny drop in the ocean of the natural ecosystem. If they really want to get behind something that might make a difference, then they should start looking at the real causes behind the decline of many fish species.
You mentioned Asian arowana (Scleropages formosus) - and you just proved how naive & misinformed a PETA supporter can be. Asian aros are NOT being wiped out from overfishing, they are being wiped out in the wild from habitat destruction. The environmental impact from gold mining, oil palm plantations, and logging (which apparently runs rampant even within national parks & protected forests) in the native range of the Asian aro (Kapuas River & its tributaries) will most likely place hundreds of species in jeopardy before they have even been discovered. None of this has
anything to do with overfishing.
For many years Scleropages formosus have been one of the most controlled ornamental fish in the hobby, with each fish requiring a ton of paperwork & permits before they can be exported or imported. The parents are recorded, the farm, each fish is inserted with a transponder, and each fish comes with a certificate with the matching transponder number. ALL of these fish are raised on privately owned & operated farms - none come from the wild.
If this is just about protecting the natural ecosystem, then please explain why goldfish, or flowerhorn, bettas, or any fish raised & bred in ponds, vats, or aquariums should be banned? Perhaps you didn't read this all the way through?
http://www.peta.org/issues/Companion-Animals/fish-in-tanks-no-thanks.aspx
The president of this great (cough-cough) organization wants ALL animals liberated, and is against anyone keeping fish in captivity - period.
This is NOT the media giving PETA a bad name, or me or anyone else nit picking on PETA, this is PETA's mantra, and one that apparently you support.
God forbid that any of your PETA comrades discover that you are keeping a a hybrid fish in a 60 gallon tank, they will probably burn you at the stake.