Aquarium Setup
        For starters, these fishes come from habitats with large open areas and very little structure.  An aquarium for a batfish should emphasize length/width rather than height. Thus “breeder” aquariums such as 40 gallon (36”L x 18”W x 12”H) would be preferable to a standard 30 gallon (36”L x 12”W x 16”H) which in turn would be preferred over a 29 gallon aquarium (30”L x 12”W x 18”H).  The size of the aquarium needed to house a batfish depends on the species and adult size of the fish.  For example I have kept pancake batfish (Halieutichthys aculeatus) and smaller specimens (5 inches or less) of Ogcocephalus spp. in tanks ranging from ten to fifty gallons equipped with appropriately sized power filters and protein skimmers.  For larger specimens I used tanks ranging from 75 – 120 gallons equipped with wet/dry filters and protein skimmers.
        
        A batfish tank should always be covered and if large individuals are kept, a weighted cover should be used.  I have had specimens ranging from small pancake batfish to foot long Ogcocephalus cubifrons jump out of uncovered or lightly covered aquariums or holding tanks.  Batfishes are reportedly nocturnal (Combs 1973, Winans 1975, Gibran and Castro 1999, pers. obs.) however I have found that they will readily acclimate to a normal day/night aquarium light cycle under a standard fluorescent bulb.  LED “moonlights” may be used to view a batfish at night or to ensure a newly acquired batfish is acclimating properly in an aquarium. 

Structure and Substrate
        Structure such as live rock should be kept to a minimum.  This mimics the natural habitat of the batfish and gives the fish the maximum area to move.  Too much structure can lead to a problem in smaller aquariums having enough bottom space for the batfish and prey may take refuge in the structure preventing the batfish from capturing them.  Hence, a reef tank is not a good choice to house a batfish.  I’ve always use sand for substrate in a batfish tank (the typical live sand sold at pet retailers is sufficient).

Filtration and Temperature
        Filtration on a batfish aquarium is not complicated.  Depending on the size of the aquarium, I usually used suitably sized power filters or wet/dry filters together with a protein skimmer.  Be sure to minimize the amount of fine bubbles from the skimmer entering the aquarium as it can cause gas bubble embolism in batfish.  Small bubbles escaping from the filter or protein skimmer into the tank can cause problems most notably when the get lodged under the rostrum.  Preventing the bubbles from entering the tank is the best way to resolve this issue.  Once the source of the bubbles is eliminated the fishes seems to be able to purge the bubbles from their bodies without any further help.  I have always kept my batfishes at temperatures between 70-82^oF with no problems. 

Problems and Diseases
        Batfishes often damage their rostrums by constantly swimming or walking into the glass.  Placing strips of black plastic at least 2 – 6 inches high (depending on the size of the tank and batfish) around the bottom of the tank may reduce or prevent this behavior.  Once the batfish has acclimated to the aquarium conditions the black barrier may be removed.  In my experience however the black plastic usually was a permanent feature as most batfish would continue swimming into the glass no matter how long I attempted to acclimate them.  I have noticed this behavior only in species of Ogcocephalus batfishes.  In one instance a 4 inch specimen of O. nasutus had severely damaged itself by running into the glass while I was out of town for a couple of weeks.  The entire rostral area became swollen with fluids.  Treatment with melafix marine however quickly reduced the infection to the point where after about a week all swelling was gone and the tissue around the rostrum had almost completely healed.  In contrast, all pancake batfish I maintained never swam or walked into the glass.

        Nearly all batfish encountered in the aquarium trade are captured as bycatch by shrimp trawlers.  All the batfish species I studied were also collected in the Gulf of Mexico by trawlers.  This method of capture causes great stress and physical damage to the fish.  Batfishes often develop bacterial infections in wounds caused by the trawl.  Once this occurs, treatment rarely works and the fish usually succumb to the infection.  This “batfish rot” was also discussed and described by Schleser (1994).  It generally consists of rapid, severe fin rot and lesions on the body.  He found that Chloramphenicol worked on the infections.  This chemical however is not readily accessible to the typical home aquarist.  While collecting batfishes for my research, I found furazone or spectrogram (kanamycin/furazone mix) to be effective in combating and/or preventing infections in newly captured batfishes.  Alternatively, I have used melafix marine to combat bacterial infections in batfishes with excellent results.  I continued to keep collected batfish under this treatment during a month long quarantine process.  I would like to emphasize that when collecting live specimens, I was aboard the trawler and immediately placed any live batfishes into medicated holding systems.  I was also selective as to which individuals to focus my effort on.  By the time a batfish reaches a retail store or the hobbyist, it may be too far gone for any treatment to be effective.  I have noticed this aspect in most batfish I obtained from wholesalers/retailers.  If possible, try to special order a net/hand caught batfish directly from a collector.

        Batfishes are also susceptible to the typical parasitic infections.   Protozoan infections like Cryptocaryon irritans  must be treated immediately, otherwise batfishes will quickly succumb to these parasites.  I have successfully used copper sulfate or formalin based medication to treat these infections.  However I have found chloroquine phosphate to be just as, if not better than copper or formalin when treating batfishes for protozoan infections.  Another potential parasitic infection with batfishes is external flukes.  A freshwater dip works well on removing them from the fish.  I have also used prazi-pro to eliminate flukes on batfishes with great success.  An important aspect in maintaining batfishes is to minimize stress.  This includes minimal disturbance of their aquarium, moving them as little as possible, and maintaining excellent water quality.

        During my studies on batfishes I noticed large numbers of parasitic nematode worms in their intestinal tracts.  These worms were especially prevalent in larger specimens (over 6 inches) of Ogcocephalus batfishes.  Schleser (1994) also noted these worms and suggested de-worming by orally administering the drug fenbendazole.  This is an extremely stressful process on the fish and the method used required knocking out the fish with MS-222 and then using a catheter to orally administer a mix of food and de-worming medicine into the gut of the batfish.  I have tried this procedure with mixed results ranging from complete success to loss of the specimen.  Over the course of my research, I noticed that individual batfish of similar size collected from the same locations at the same time could have varying quantities of intestinal worms.  Some were severely infested, but others had few if any worms.  I no longer de-worm any batfish I collect as I have noticed no difference in their long term survival without the treatment.

Feeding
        Feeding batfishes is not terribly difficult, assuming of course a healthy specimen is obtained.  Live foods are usually required to initiate feeding.  Small batfishes may be fed live mysids, live Hawaiian red shrimp (Halocaridina rubra) or enriched live brine shrimp.  Larger individuals may be fed live ghost shrimp.  Once the batfish has acclimated to the aquarium it may be trained to take pieces of fresh, raw seafood such as shrimp, scallop, squid, or fish.  Soaking foods in commercially available vitamin supplements or gut loading live ghost shrimp are useful methods to help ensure proper nutrition for your batfish.  As a general rule I feed my batfishes every two to three days.  Most specimens I have kept tend to eat two to four pieces of appropriately sized food before ignoring further offerings.  

        As an example, a four inch Ogcocephalus vespertilio would eat two or three vitamin soaked frozen ghost shrimp or krill, about an inch long, every other day.  A 4 inch O. nasutus ate at least 10 small (half inch) ghost shrimp every other day while smaller two or three inch specimens ate between two to six half inch ghost shrimp during feedings.  In contrast pancake batfish usually ate four to six Hawaiian red shrimp daily although I have seen individuals eat up to ten in a feeding session.  Individual batfish may learn to associate their keeper with food and may walk to the front of the aquarium or perform luring behavior when the aquarist is present.  I have only been able to train Ogcocephalus species of batfish to take non-living food on a regular basis.  During my research, only one pancake batfish I maintained ever ate non-living food (frozen mysids, fresh dead Hawaiian red shrimp).  More recently, I had three pancake batfish that ate 4 or 5 frozen mysids daily.  Interestingly, they were in a tank with another four pancake batfish, none of which showed any interest in the frozen mysids. 

Compatibility
        Tankmate options are rather limited with batfishes.  Due to the specialized maintenance and slow, methodical feeding nature of these fishes, I recommend keeping batfishes alone.  Fishes that may mistake the batfish for a piece of live rock such as angelfishes, butterflyfishes, blennies, tangs, puffers, and triggers should be ruled out as tankmates.  Aggressive feeders including eels, groupers, wrasses, damsels, hawkfishes, and squirrelfishes should also be excluded.  Conversely, larger batfishes will eat (or try to eat) small fishes like gobies, basslets, and even small eels (I have found snake eels in the stomach contents of large batfish).  I also routinely kept similarly sized batfishes of both the same and different species together.  While I have kept several individual batfishes (both Ogcocephalus spp. and/or pancake batfish) together with no apparent compatibility issues, Schleser (1994) reported dominance hierarchies in Ogcocephalus spp. with subordinate individuals failing to do well.  I have included lists of fishes (of appropriate sizes) I have successfully kept with batfishes.  However please note that many of them have specialized and specific requirements that must be taken in account in addition to the requirements needed by batfishes.