Some consider this guy the holy grail of predatory fish, Rhinopias frondosa, aka the weedy scorpionfish. I've had this guy coming up on 4 years and I thought I would share some info from what I learned about this species. They seem to be hard to keep, as I have never known anyone keeping one more than several months. Finding a healthy one from the start is the biggest challenge. You do want to acclimate this fish properly, they do not seem to like severe changes in water chemistry. Once acclimated they are not too particular. Even if they take to dead food, you still want to maintain a dominant live diet.
Most suppliers know better than to keep this fish in copper, even a sub therapeutic dose will prove deadly in no time. If you see one at a lfs and you are interested, if possible, spend some time observing, as much as 2 weeks the better. Check around the tank for stringy poo and make sure the store is not feeding them salt water water fish.
Just like with other predatory fish, internal parasites seem to be a scrouge among these guys. The problem is they are very sensitive to meds, even gc and prazi. I've mentioned this before, the reason internal parasites seem to be so prevalent among predatory fish, is because along the way there are fed fresh dead and dying, diseased fish. I have witnessed first hand lfs scoop up a dying fish, obviously diseased and toss them in a tank with a scorp, lion, angler, etc. As with all members of the Scorpaenidae family, the rhino has a very robust slime coating, especially thick and will shed occasionally. Because of this they are resistant to protazoan diseases but internal parasites are a major concern. I did lose one in qt, but have since treated one successfully for internal parasites. While treating these guys has proven near impossible, I finally figured out to split the dose into 3rds and dose 8 hours apart. Make sure the water is aerated with surface agitation or even an air stone. Have fresh water available for an emergency water change. Plan to have at a couple of hours after each dose to observe, if extreme stress do an immediate water change. Split dose further down but do not take more than 24 to complete dosage, as the half life will weaken the dose too much. Once determined they have internal parasites, you will either clear them or they will die anyway.
While these guys do seem to take dead food, it is always a challenge and not a good idea to plan to keep on a dead diet only. Like many other predators if fed a dead only diet, one day they just may stop feeding, and if you haven't planned a tank or source for live feeding, you will be in trouble. They can be challenging as every time you feed them they can act like the first time you've fed them. You'll have to trick them by getting a quick feeding response, and sometimes they just won't feed. They will take a chunk here or there but never enough, and over time slowly waste away. They appear to be mainly fish eaters and mollies are a great diet. All the other pitfalls I've mentioned in earlier threads apply to this fish when it comes to feeding dead food, and a fast/gorge feeding schedule. Sadly even after I helped acclimate and establish rhino's for 2 individuals, they just would not follow through on a live diet, and they both died several months in. This happens all the time with certain species and people just will not take responsibility for the fact they let their fish starve or die of malnutrition. My 7" rhino eats about 5-1.5-2" mollies a week, so if you don't have a good inexpensive source, it can be pretty pricey. He will snack down a big fat ghostie if one wanders up to him, but he won't chase one down.
They are happy to live alone like in a 40B or in a community tank large enough for fish too big for them to eat. Don't keep with aggressive fish or nippers that may pick on them. I wouldn't put them in a larger community tank until they are accustomed to your feeding method. I hand feed mine by cupping a molly and releasing them towards them. You can also use the net method, and if in a smaller species just let them hunt on their own with some herding if necessary. They like open areas with maybe an alcove, not so much a cave dweller. They do like a plateau or two at different heights. Currently mine is in a 90g with 4 lions.
This is very fascinating and enjoyable fish to keep.
