Freshwater stonefish   4/15/11
Hi, I bought a stone fish in the a local pet store just recently.
<An interesting brackish to marine species.>
They had him in freshwater with a pH of about 7.5.
<I see. Well, he won't put up with this indefinitely, though in the short term won't do any harm.>
I've been doing some research and I believe this fish to be of the type Batrachus trispinosus.
<This species -- now called Batrachomoeus trispinosus -- is certainly traded widely. Also review Allenbatrachus grunniens (from Southeast Asia) and Batrachoides surinamensis (from South America).>
I did some more research on the fish and I've found sites that say they can live in freshwater, brackish water, or saltwater.
<They are indeed migratory to some degree, and common enough in estuaries where the salinity will vary from fresh to salt and back again.>
Which is the best environment for them?
<Probably marine, but they'll do well in brackish water too, SG 1.005 at 25 C/77 F upwards.>
Right know I have him in a 37 gallon freshwater aquarium with a Nigerien upside down catfish and two Apollo sharks at a pH of about 7.3 and no salt present.
<A short term solution at best. Given Batrachomoeus trispinosus gets to about 30 cm/12 inches long, and will swallow anything up to two-thirds its length, all these tankmates have the potential to become meals. These fish are notorious biters, and can, will bite the fishkeeper too.>
Would it be possible for me to alter this tank enough so it would be a good environment for him or should I put him in a different tank?
<Does need its own aquarium. All these Toadfishes (rather than Stonefishes) are best kept alone. They're very hardy and easy to keep, given the right conditions, and swim about little, so you don't need much space. A single specimen should be fine in as little as 180 l/45 gallons, given good filtration and limited feeding. They're easily weaned onto dead foods, by the way, so be sure to avoid the use of live feeder fish which will cause all sorts of problems.>
I know he will need a bigger tank, and I have one, a 75 gallon tank, I just mean for now. He is only about 4 inches. Thanks, Alex
<A nice fish; enjoy! Cheers, Neale.>

Hello Bob,
> There's a question in today's FAQs about "freshwater stonefish". Here's a picture of this beast, if you want it. Same family as Opsanus spp., if you want to link the freshwater species FAQ to the saltwater FAQ. Most of the freshwater ones are brackish-marine anyways.
<Ah yes. Thanks, B>
> Cheers, Neale