Fish of the week #2-nemateleotris magnifica/n. decora-firefish/purple firefish


Sir Brian The Lenient
Staff member
RC Mod
Nemateleotris magnifica Firefish
Nemateleotris decora Purple firefish

These two fish are both members of the Dartfish family. They reach about 3 inches in length. They feed almost exclusively on meaty foods such as mysid and brine shrimp, and frozen food preparations for carnivores. They feed out of the water column, rarely taking food from the bottom of the tank.

Both the n. magnifica and the n. decora are timid fish. They will usually make their home in a cave or opening at the base of rockwork in the tank, sometimes burrowing into the substrate. They will quickly dart back into their cave when frightened. For this reason, it is important these adequate hiding places be provided. They are notorious for jumping out of tanks, so minimizing their stress is important.

These fish are completely reef-safe, and compatible will other fishes. It should not be housed with agressive tank mates or may not be able to feed. The firefish can sometimes be kept together in a large tank, but often 1 firefish becomes agressive towards others and may continually chase them.
Personal experience:

I have probably had several of these fish, both the purple and the regular firefish, and probably won't buy anymore until I get some eggcrate or something over my tank. I had at least 6 carpet-divers, and they don't do well out of water :(. It is no fun to keep buying them just for them to bail out of the tank. FWIW, I added 3-4 to my 180 and never saw any agression. Mine schooled together (both the purple and the regular), but I have heard of others who had no luck adding more than one.

I am down to one n. decora, and he is a beautiful little fish. He makes his home at one end of my tank, and rarely leaves that spot. When I feed the tank, he patiently waits for food to drift his way.

I've only ever had one N.decora. Still have him and he's quite active. He has a bolt hole that he likes to dart to when he feels threatened but he seems to like to cruise around the majority of the tank. FWIW, when I added a surge device to my tank (lots of water flow in this tank) he became even more active and seems to enjoy riding the currents. He eats just about any foods and, no he doesn't eat any copepods (many people claim to have seen N.decora picking at the rocks and sand).

Had a Nemateleotris magnifica, one of my first fish. Tried to ride the big carpet wave :( . I was watching him in the tank, went to the kitchen for a soda, come back ten minutes later; guess he didn't like the air. Very nice looking fish!
I have one of each in my 120 for over a year now (the Mag was added a month before the Dec). They reside in little caves on opposite ends of the tank. Each will periodically wander into the others "domain" with no hostilities ever shown.

My canopy is fully enclosed, but the magnifica has twice jumped into the corner overflow, and once got trapped in it's cave after a minor rearrangement. I wondered for about a week what was up, cause I could see him through a little porthole window, but he never came out!

Both are awesome fish.
I got a N. magnifica in my 100 g tank for about 2 months. I wanted to add another to make a pair but in Corpus Christi, it is really hard to got good livestock. I waited for two months and was not able to get a mate for it. Finally a LFS got several N decora instock. I asked the owner to put two together for me. I was lucky, they paired up, so I bought the pair. I got three one N magnifica and two N decora for one week. I was about to celebrate that they got along and I don't have to remove the lone N magnifica. One day I just did not see the N magnifica anymore. He must jumped over to the sump and got eatten by my large crab in there. There were never any hostility among the three fish. Now I only have a pair of M decora in my tank for the last 4 weeks. Both seem to do well and sare the same cave. I think I have a pair.
I find that my N magnifica is more active than the pair of decora that I now have. All three are very beautiful and peaceful fishes. I love them.
I've had one N. decora in my tank for a little over a year. He hangs in the water column just above my Tridacna maxima. Interestingly he doesn't bother the clam at all however; if the blenny goes anywhere near the clam it closes.

I'd originally purchased a "mated" pair from the LFS with one being substantially larger. Soon after getting them into my quarantine tank the larger one began chasing the smaller. I kept a close eye on them and all was well. After a couple of weeks I added them to the main tank. The small one disappeared after two days never to be seen again. Whether it was my yellow tang or the other firefish I can't be sure.

The firefish took a bite or slash from my yellow tang just after I added him and developed an infection that I can't remember the name. The fish refused to be trapped and removed to quarantine but healed on his own. I later read they are extremely resilient to disease and parasites (Scott Michael Aquarium USA 2001 Annual).

Yup, Jumpers. Had pair for about three months when one day I found both on the floor. I have to say that blue damsel had a bit of a smerk on his devilish face. One of these days, I'll catch the devil then try again with the firefish.

Dave, thanks for the thumbs up. It is appreciated.

Just curious if anyone has covered their tank to prevent carpet divers, and, if so, what was used (i.e. eggcrate). I have considered eggcrate, but have been worried about how much light it will deflect.

My hood is relatively closed. It's open at the back to allow for the filtration, plumbing, fans, etc. Other than that there is no other means of covering the top of the tank. I've had my firefish for about 6 months now without a "leap of faith" from the little bugger...knock on wood.

Hey Brian,
its my xperince that if you keep more than 2 decoras,a "pair" soon will team up and chase the others till they`re dead`n`gone.
The manifica on the other hand is very much sociable,you can keep a little school of these fish.There a sight :)
When diving in Indonesia,the manifica we spotted was always in schools,the decoras in pair.Itneverfailed.
Maybe its worth pointing out that two other spicies the Nemateleotris Helfrichi and the Ptereleotris Evides(Blackfin Dartfish)also is both very pretty and reefsafe.In Denmark however these two is not imported that often.

BTW would it not be a good idea to post pics along with these threads ????
If some1 could tell me how 2 post pics,I would do it ;)

Maybe we could also make a pic achive,so reefers that can`t remember fish by name,myself included :D,could go look,thus get the best out of these threads??

Well this is work for administrators and moderators,maybe

Just a few ideas
Nice work Brian
Looking foreward to #3 FOTW
Keep Reefing
Michael, thanks for the real-life experiences. It is always fascinating to get viewpoints from those who have seen the fish in their natural habitat.

Pics are a good idea. If anyone has one available, jump right in, if not, I will try to get one.


Perhaps the best way to keep them from jumping out (if you have a canopy, not pendants) is to use the eggcrate or screen to build a wall over any openings in the back?

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BTW there are a few variations to the Decora. I think the one I got was from the indo-pacific, he doesn't have as much purple as the one pictured above. I originally had two, but one has disappeared, he did have a possible broken jaw when I got him though.

So, the next fish will be a bi-color blennie, right Brian. The only fish I have in my tank are the Hepatus Tang(the first fish of the week), N. Decora(the 2nd fish of the week) and a bi-color. It just seems fitting :D
A job well done Brian

My firefish--well first fish in my tank. Is not shy at all, is the only fish that hangs around with my hand down in the tank. Eats flake food. Takes no crap from a tang 8 times his size. Obviously is not a jumper(yet).
So, the exception to the rule?

Pi - Formerly known as 'the quantity which, when the diameter is multiplied by it, yields the circumference.'
Smithsonian, May 2000
Brian, I put eggcrate over the top of my tank after my yellow assessor jumped. There's still plenty of light in the tank, and that's with just two 110W VHO bulbs. Got another yellow assessor, too. :)
Thanks, Robert. I think it is a necessity if you want to keep firefish, unless your canopy is closed. Protecting them from jumping into overflows is a good idea, too.

What about the Helifrichi's Firefish?

There on ffexpress for 250$.

Is that really a 250$ fish? what are its habits/habitats?