here's some info:
Freshwater Stonefish
Factoids
How to Care for Your Freshwater Stonefish
Aqualand's inside scoop on Batrachus trispinosus
Origin
N.W. Australia, Thailand, Indonesia, New Guinea
Temperature
Tropical
Size
12 inch max
Water
Flexible. Brackish.
Substrate
Very flexible
Security
Likes to get behind anything
Foods
Likes fish
Breeding
No idea other than egglayer
Threats
Poor water conditions
  
 
Name: Freshwater (really brackish water) stonefish, aka freshwater lionfish, freshwater toadfish, and freshwater frogfish belong to a curious group known as toad fish. Probably the "freshwater" in their moniker is to distinguish them from their saltwater cousins. Well call them freshwater stonefish because they try to look like a harmless lumpy stone until a swallowable fish swims by.
Venomous? All of the toadfish cousins are venomous to some extent. We do not recommend the finger test to find out just how venomous these rascals are. Experience is the best teacher, but its also the most painful and sometimes the most expensive. Lets just say youd best not touch your stonefish (and net him carefully).
Origins: You can find (if you look very closely) freshwater stonefish in many countries in the Indo-Pacific rim. Theyre just one more reason not to go wading barefooted. In the tropics, they fear stepping on corals, sea urchins, stingrays, and freshwater stonefish. In Des Moines we fear stepping on broken glass and bullheads.
Brackish Water: Freshwater stonefish or whatever they call them in your neck of the woods come from tropical areas where rivers flow into the ocean (estuaries). This means they live in brackish water. When the tide goes out, they live in freshwater. When the tide comes in, they live in river water mixed with ocean water (brackish water). They are flexible little beasts.
Substrate: Sand might not be the best substrate. Freshwater stonefish show up well over white sand. However, they kick up the sand a bit and it settles on them. If agitated, they really kick up a lot of sand. On the other hand, they blend into natural gravels. Experiment with different substrates until you find one that appeals to you.
Skulkers: Freshwater stonefish skulk 98% of the time. In some cases they get behind bulky objects in their tank. In others, they wedge themselves into a corner or cave. Big guys sometimes just loaf on the bottom looking like a big lumpy stone. Thus the name.
Walkers: Upon occasion your freshwater stonefish will stomp around on his specialized fins. Hes about as graceful as a toad. Thus the "toadfish" name as the Ontarians in Ontario call them, eh.
Nocturnal: Some freshwater stonefish will zip out and inhale their lunch as soon as you drop in another smaller critter with fins. Most prefer to wait for the cover of darkness to dine at a more fashionable hour. GIGO (goldfish in, goldfish out) overnight.
Breeding. Probably not going to happen. Although, Traviss toadfish (as he calls it, because hes an Ontarian and cant help himself) did lay eggs. One of mine laid a few yellow (possibly immature) eggs. And Kara Zeinner from Indianapolis also reported white egg production. If I recall correctly, stonefish scatter their eggs. No fry reports yet.