If you ever suffer those pesky little rust-brown flatworms the usual prescription is either a Sixline wrasse, Springer’s Damsel, or a Psychedelic mandarin, Synchiropus picturatus. These are all good choices but the species we use to best effect in my LFS is the humble Ocellated dragonet, Synchiropus ocellatus. Also sold just as the “Scooter Blenny,” (Neosynchiropus,) ocellatus is plain when first viewed and won’t appeal to reefkeepers who lust just for color, but they are masters of camouflage in the wild, and what they lack in color they make up for in usefulness. Males can erect an impressive dorsal fin while displaying.
We can count the number of times we’ve actually recommended dragonets, mandarins, and scooter blennies on one finger, but in the last five years this larger-than-average species has proved devastatingly effective at controlling Convolutriloba retrogemma in our coral tanks, their effect is noticeable within a few days, yet we don’t end up with a skinny, emaciated scooter in the months and years that follow.
The same goes for the species sold as the Pink Scooter Blenny, Synchiropus stellatus, which again, although much more plain than Synchiropus splendidus or the Ruby Red Synchiropus sycorax, it seems less prone to starvation yet is highly effective at flatworm control, for us at least.
Take note, the keeping of any dragonet requires a competent owner as well as a mature tank, and a Sixline wrasse, Springer’s damsel, or a Melanurus wrasse will be a better, more sensible, much hardier choice for many. But if you need some alternate flatworm control in a large mature coral flat give them a try.
Eight fish that will eat flatworms in reef aquariums
- Springer’s damselfish, Chrysiptera spingeri
- Sixline wrasse, Pseudocheilinus hexataenia
- Leopard wrasse, Macropharyngodon meleagris
- Yellow wrasse, Halichoeres chrysus
- Melanurus wrasse, Halichoeres melanurus
- Psychedelic mandarin, Synchiropus picturatus
- Ocellated dragonet, Synchiropus ocellatus
- Pink scooter blenny, Synchiropus stellatus
Other flatworm predators
Many wrasse species will eat flatworms and you can help them find them by blasting rock, the tank glass, and corals with a turkey baster. Dislodge flatworms and Chromis and other Chrysiptera species damsels will also eat them. For inverts, the Blue velvet nudibranch, Chelidonura varians, is a flatworm specialist although it can be tricky to keep alive in its own right. Even hermit crabs will predate flatworms if they can get to them.
Image credits
Brian Jeffery Beggerly from S’pore, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
Izuzuki, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
AquariaNR, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>, via Wikimedia Commons
Steve Childs, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons
Fedtred, Public domain, via Wikimedia Commons
