hello; I still say this is the way to do it. Get the tank first.
Hello; I guess if you had a 55 gallon sump, lots of pumps and media, did over 50% wc two or three times a week the 55 available for the fish might work for while with a small arowana. Not for very long.
Hello; I get the impression this is not your idea. Out of your control. So try to not get an emotional attachment to the fish. There will not be much you can do to prevent another episode.
A 55 gallon with a baby arowana is just a short term thing at best. In a 55 with a divider and another fish reduces the short term viability of the setup even more. To put it another way, without a much larger tank within months the new fish has little chance.
There are a number of fish that can be kept in a 55 when mature. Not many of the bigger fish however and for sure not an arowana.
I have a 55 with one mature female angel fish and about six smaller fish. Very light stocking for sure, but after five decades I have learned many lessons. I like a nice interstate wide tank path and not a "tightrope" tank anymore.
If another arowana is picked up and if you feel obligated to try to keep it healthy, then I suggest you either keep this thread going or start another thread asking for advice on how to manage under the current circumstance.
Good luck and near as I can tell you do not own this.
