Harlequin filefish, 2nd month

So, it’s been two months since I got the Oxymonacanthus longirostris. I have detailed how it came to me in the first status report but as a reminder: this fish came to a local fish store by accident and it was decided that I should give it a try because I had several different Acropora species growing in my tank. Unfortunately I had just replaced my previous tank with a new one so all my colonies were relatively small but even then it was more than the dealer had in his tanks.

Last month has really been quite uneventful, my Oxymonacanthus longirostris has been like any thriving aquarium fish, eating flake foods with gusto and being a lively and active specimen.

After observing closely this fish tens of hours in my reef aquarium I can provide these notes:

What ever they are feeding off corals, they are not eating polyps! These fishes seem to be very selective feeders, always going through coral branches and keeping a close eye on the coral surface. When it sees something to eat it will quickly take a nip and continue browsing. Growing tips of corals are very rarely nibbled at.

There are never bite marks or other visible damage. Actually, I would say that the corals on which they spend the most time seem to be the healthiest.

I’ve seen him nibbling on Acropora, Stylopora, Montipora, Cyphastrea, Acanthastrea, Micromussa and Capnella. It has not touched Echinophora, Pachyseris, Favia, Turbinaria, Catalaphyllia, Subergorgia, Isis, Rumphella, Aiptasia, corallimorphs, zoanthids nor hydroids.

He also eats small invertebrates from the rocks, although only sporadically.

After starting to eat flake foods he has not been eating from coral surfaces as much as before.

It is tempting to speculate that they are actually eating the slime corals produce and small creatures living on the coral. It might be an interesting experiment to try this species to control coral parasites.

Just like in nature, Oxymonacanthus will keep coral polyps closed during the day. I think this as a positive feature.

These fishes need to be fed several times a day. It seems like they have very short digestion system. The fish can be noticeable thinner at morning even though they spend extremely little energy when they are asleep.

They need a thick Acropora growth so that they can wedge themselves between the branches using the first two dorsal spines.

It might be important to have right Acropora species when first introduced to the tank. My individual would not touch anything else than the “green slimer” Acropora for a few first days. He would gradually expand his feeding area and start to sample other corals.

All other fishes seem to completely ignore him, even the large Acanthurus achilles I have.

Tags: Husbandry, oxymonacanthus

This entry was posted on Thursday, April 16th, 2009 at 18:21 and is filed under Fish. You can follow any responses to this entry through the RSS 2.0 feed.