I've kept a few, my first going back 25 years. These are very difficult fish to keep and I am still very frustrated as to the success in keeping these guys long term. I do have some information I would like to share for those interested. Be forewarned, they are not for everyone and do take special care. They are sedentary creatures and are best kept in a species tank, they don't last long in community tanks. For long term success they will need to be fed a live diet. They can eat fish equal to their own size, and if eating too large of fish, they both usually die. Over feeding is a big concern, usually in the form of feeding too often. You don't want to expose to air, as thy can gulp air and it is hard for them expel it, many times dying if it happens.
The most popular of the bunch is the warty, wartskin angler, Antennarius maculatus. My favorite is the painted angler, Antennarius pictus. Some of the others seen around are the giant angler, Antennarius commerson; I see the sargassum and marble mouthed around, as well as the hairy. I would stay away from the pygmy, they never live. Juveniles can sometimes be confused and some are sold as assorted because the supplier is not able to ID them. Here a good reference if you are trying to ID one http://frogfish.ch/species-arten/all-frogfish-species.html
Depending on the species, I prefer tanks from 20-40g. These size tanks help you manage feeding better, and they really are sedentary and do not swim, per se. They have jet packs and may propel themselves from one point or another and I even had one that would swim(kind of) each evening when the whites went off. He would blast off bouncing his feet off the glass and you could see his jet packs pumping from behind his front legs, so funny. They are fine with medium, lps flow, and will find spots to protect themselves if the flow is too much. I also had a warty that would do this kind of floaty thing, where he would float around the tank looking for food, I called it his recon missions. So with too much flow they will just be less active. They also don't care for high light, some even less so and hang out in a cave all day while the whites are on. Some prefer caves, like the painted; so included a cave in their scape is a good thing. Provide some open spaces and different levels of elevation. It is fun to keep them in a reef or a macro tank. They are like chameleons in a sense they will imprint onto their environment. Over time a colorful angler will turn blah if kept in a tank of plain rock. Many of them live among colorful sponges and various colored macros in the wild. So keeping them with similar colored corals or red and orange macro will encourage them to keep their bold colors. I kept one in a tank with Living Color fake corals once and maintained his orange and red coloring.
Feeding, your biggest challenge, never think that you are 100% convert these guys to a dead food only diet. Many just will not accept it from the get go, no matter how you plead. If you do them them to take dead food, they will usually suffer from nutritional deficiencies and be dead within a year. They will never accept the dead foods necessary to provide them with proper nutrition, and supplementation will not help, they likely need the live gut flora and other elements found in live food. Any one telling you are keeping these guys for multiple years feeding them krill and silversides just are not being honest. If they do take dead food it is usually not enough and just wither away, literally starving to death right under your eyes. Some may take dead food for a while, but it is always inevitable, one day they will just stop. Sometimes you can jumpstart them back onto live but most times, if it's been a while, not. Also, you want a bump on a log, basically no different than silicone model, feed them dead on a stick. They will just park themselves into the feeding spot and may never move again until they die. Depending on the species, and mostly based on size; the choices of live food are ghost shrimp, guppies, and mollies. While they can eat very large prey, it is best to feed a few smaller items. It's pretty common if they eat something very large, they end up dying. In the wild they eat on a gorge/fast routine, and in captivity it's best to mimic this schedule. If is an itty bitty guy, I've raised wartys as small as an inch, it's ok to feed every other day. As they row you want to spread their feeding times further and further apart. Once mature a weekly schedule is good, while I have seen every 10 days work. You want to manage their feeding and not just dump a bunch of food in all at once. Feed them until you see a nice bulge in their belly. Feel out their schedule by allowing them to get active, going into hunting mode, before you feed them again. They also poop like dogs, you can literally see the turd on the substrate, paying attention to this also helps you get into their feeding schedule. Feeding too often is bad news, because of their metabolism, the undigested food can start to build up, building up gases in their guts. This can start to indicate by this buoyant type activity, if you see this, stop feeding for a while and start allowing more time between feedings. Magnesium has been known to help with digestion, so at least keep your mg at reef levels, even at 1400ppm is safe for corals and I've found to be beneficial.
If you must house them with tank mates be mindful of a few points. Any tank mates must be larger that the angler, full grown, and you still must get them live food. Do not house them with any aggressive species that may injure or pick on them, even mild mannered fish that nibble. Because of their sedentary nature tangs and angels and such will nibble at them. This will cause them stress or injuries that many times turn into bacterial infections. They will cannibalize each other, and in most cases because of the size of each, they both die. Remember you read it here if you decide to do it anyway, because eventually it will happen. They are ambush predators that do attack and are not fast, they set up shop and wait. I have had damsels and peppermint shrimp live for months before ending up prey. They will watch and maneuver until they catch them one day. I've seen them figure out where someone sleeps and wait outside their hidey hole. This is their nature, it does not waiver if the fish is healthy. You can use fish like damsels as color and movement, but knowing one day they may be food.
They do not tolerate meds and chemicals of any kind. I haven't tried my new method of splitting dosages for internal parasites into thirds; which has worked on some sensitive scorps. At this point I have not seen an angler successfully treated with any med. Getting through treatment doesn't mean success if they die shortly afterwards. But they do come in with internal parasites and if so, will need to be treated. That's where I would break up general cure dosage into 3rds. They can get ick and other protozoan diseases and can not tolerate copper or cp. On some species ick is very hard to see, because some have this fuzzy type of camo. They can live months with ick but will eventually succumb. Never use salt water fish as food because eventually you will spread disease.
I would consider keeping them in lower temps, at least at low end of tropical, maybe even lower if possible. While I haven't seen enough to consider a possible point to keeping them longer, it does have some considerations. Several divers have told me they see them at deeper depths in water under 70 degrees. Think about other species that had a dismal captive lifespan until people figured out they needed lower temp. So far I have one hobbyist keeping her angler at around 72 degrees, and so far she has kept this one twice as long as any others she's ever kept, over 3 years now. She has also followed some my other points with feeding and mg. While I have heard of people keeping them as long as 5 years, I've never met anyone keeping one for even 2 years except the person I just mentioned. I have kept a warty over 3 years and a painted over 3.5 years, that's my best and it's not good enough.
The most popular of the bunch is the warty, wartskin angler, Antennarius maculatus. My favorite is the painted angler, Antennarius pictus. Some of the others seen around are the giant angler, Antennarius commerson; I see the sargassum and marble mouthed around, as well as the hairy. I would stay away from the pygmy, they never live. Juveniles can sometimes be confused and some are sold as assorted because the supplier is not able to ID them. Here a good reference if you are trying to ID one http://frogfish.ch/species-arten/all-frogfish-species.html
Depending on the species, I prefer tanks from 20-40g. These size tanks help you manage feeding better, and they really are sedentary and do not swim, per se. They have jet packs and may propel themselves from one point or another and I even had one that would swim(kind of) each evening when the whites went off. He would blast off bouncing his feet off the glass and you could see his jet packs pumping from behind his front legs, so funny. They are fine with medium, lps flow, and will find spots to protect themselves if the flow is too much. I also had a warty that would do this kind of floaty thing, where he would float around the tank looking for food, I called it his recon missions. So with too much flow they will just be less active. They also don't care for high light, some even less so and hang out in a cave all day while the whites are on. Some prefer caves, like the painted; so included a cave in their scape is a good thing. Provide some open spaces and different levels of elevation. It is fun to keep them in a reef or a macro tank. They are like chameleons in a sense they will imprint onto their environment. Over time a colorful angler will turn blah if kept in a tank of plain rock. Many of them live among colorful sponges and various colored macros in the wild. So keeping them with similar colored corals or red and orange macro will encourage them to keep their bold colors. I kept one in a tank with Living Color fake corals once and maintained his orange and red coloring.
Feeding, your biggest challenge, never think that you are 100% convert these guys to a dead food only diet. Many just will not accept it from the get go, no matter how you plead. If you do them them to take dead food, they will usually suffer from nutritional deficiencies and be dead within a year. They will never accept the dead foods necessary to provide them with proper nutrition, and supplementation will not help, they likely need the live gut flora and other elements found in live food. Any one telling you are keeping these guys for multiple years feeding them krill and silversides just are not being honest. If they do take dead food it is usually not enough and just wither away, literally starving to death right under your eyes. Some may take dead food for a while, but it is always inevitable, one day they will just stop. Sometimes you can jumpstart them back onto live but most times, if it's been a while, not. Also, you want a bump on a log, basically no different than silicone model, feed them dead on a stick. They will just park themselves into the feeding spot and may never move again until they die. Depending on the species, and mostly based on size; the choices of live food are ghost shrimp, guppies, and mollies. While they can eat very large prey, it is best to feed a few smaller items. It's pretty common if they eat something very large, they end up dying. In the wild they eat on a gorge/fast routine, and in captivity it's best to mimic this schedule. If is an itty bitty guy, I've raised wartys as small as an inch, it's ok to feed every other day. As they row you want to spread their feeding times further and further apart. Once mature a weekly schedule is good, while I have seen every 10 days work. You want to manage their feeding and not just dump a bunch of food in all at once. Feed them until you see a nice bulge in their belly. Feel out their schedule by allowing them to get active, going into hunting mode, before you feed them again. They also poop like dogs, you can literally see the turd on the substrate, paying attention to this also helps you get into their feeding schedule. Feeding too often is bad news, because of their metabolism, the undigested food can start to build up, building up gases in their guts. This can start to indicate by this buoyant type activity, if you see this, stop feeding for a while and start allowing more time between feedings. Magnesium has been known to help with digestion, so at least keep your mg at reef levels, even at 1400ppm is safe for corals and I've found to be beneficial.
If you must house them with tank mates be mindful of a few points. Any tank mates must be larger that the angler, full grown, and you still must get them live food. Do not house them with any aggressive species that may injure or pick on them, even mild mannered fish that nibble. Because of their sedentary nature tangs and angels and such will nibble at them. This will cause them stress or injuries that many times turn into bacterial infections. They will cannibalize each other, and in most cases because of the size of each, they both die. Remember you read it here if you decide to do it anyway, because eventually it will happen. They are ambush predators that do attack and are not fast, they set up shop and wait. I have had damsels and peppermint shrimp live for months before ending up prey. They will watch and maneuver until they catch them one day. I've seen them figure out where someone sleeps and wait outside their hidey hole. This is their nature, it does not waiver if the fish is healthy. You can use fish like damsels as color and movement, but knowing one day they may be food.
They do not tolerate meds and chemicals of any kind. I haven't tried my new method of splitting dosages for internal parasites into thirds; which has worked on some sensitive scorps. At this point I have not seen an angler successfully treated with any med. Getting through treatment doesn't mean success if they die shortly afterwards. But they do come in with internal parasites and if so, will need to be treated. That's where I would break up general cure dosage into 3rds. They can get ick and other protozoan diseases and can not tolerate copper or cp. On some species ick is very hard to see, because some have this fuzzy type of camo. They can live months with ick but will eventually succumb. Never use salt water fish as food because eventually you will spread disease.
I would consider keeping them in lower temps, at least at low end of tropical, maybe even lower if possible. While I haven't seen enough to consider a possible point to keeping them longer, it does have some considerations. Several divers have told me they see them at deeper depths in water under 70 degrees. Think about other species that had a dismal captive lifespan until people figured out they needed lower temp. So far I have one hobbyist keeping her angler at around 72 degrees, and so far she has kept this one twice as long as any others she's ever kept, over 3 years now. She has also followed some my other points with feeding and mg. While I have heard of people keeping them as long as 5 years, I've never met anyone keeping one for even 2 years except the person I just mentioned. I have kept a warty over 3 years and a painted over 3.5 years, that's my best and it's not good enough.
