Fancy a challenge? Expert marine fish breeder Matt Pedersen takes a look at spawning the Longnosed hawkfish in the aquarium — and the first part of that challenge is trying to get a pair!
I understand that while the Longnosed hawkfish (Oxycirrhites typus) has been spawned in captivity, it has not yet been successfully reared to juvenile stage.
Current knowledge suggests that all hawkfish are protogynous hermaphrodites, meaning they start life as female and the terminal sex is male. Most marine aquarists are more familiar with this lifestyle in wrasse and anthias. In fact, much like these families, some Hawkfish are thought to live in harems.
I once tried to pair the Longnosed hawkfish, but it did not go well! I selected two 5cm/2” specimens and placed them together in a tank. They immediately began to circle, trying to attack each other. After 20 minutes trying to separate them, we realised this wasn't going to work.
I've had similar experiences when trying to pair two small specimens of Bicolor angelfish. It seems that the problems stem from each fish's desire to be boss and since they are the same size and equally matched, neither backs down.
Successful pairing of hawkfish seems more likely to occur when there’s a noticeable size difference between mates, which might mean looking for the smallest specimen you can and then a second at least 1-2cm/0.4-0.8” larger.
Starting with large hawkfish is to be discouraged. You increase your chances of having two males and we don't know that hawkfish can revert to being female.
Ideally, you want the smaller fish to realise there's no chance of being dominant, so minimising aggression. Still, it would be wise to introduce them in a way they cannot initially cause physical harm, such as housing the smaller specimen in a clear container for the first week.
Once you have a compatible pair, conditioning them to spawn simply involves heavy feeding with quality foods. Having your lights timed helps the fish get in tune with day-night rhythms and, in time, they should do what comes naturally.
Hawkfish are pelagic spawners that make a spawning rise, so have a well fitting lid on the spawning tank. This also means the fish may need considerable vertical height to spawn successfully. For this reason, some breeders of pelagic spawning fish prefer vertical barrels as broodstock aquariums.
Beyond that, there are no specifics. You'll have to collect the eggs, incubate and hatch them, and figure out how to rear them yourself!
Mandarins (Synchiropus sp.), dwarf angelfish (Centropyge sp.) and the Harlequin filefish (Oxymonacanthus longirostris) may have similar starting points and could provide the tools needed to get the job done.