Acceptable Refugium occupants

DanInMichigan · Oct 30, 2019

For those of you who run diverse refugiums ( vs those who run a single species of macro only ):

What types of life to you consider 'legal' for occupation in your refugium. This area of the tank is meant to be a refuge for life that either cannot thrive in the display tank, or are unwanted in the display tank. So as you move up the food chain, potential occupants of the refugium become impossible to keep because they get eaten. ie: defeating a purpose of your refugium.

So, what do you consider acceptable to have in yours? Copepods and macros I think are a given. what about snails? What about a crab? A filter feeder? Do you think any kind of fish is acceptable?

lapin · Oct 30, 2019

It has a lot to do with size of the fuge. If you had a 100 gallon fuge you could keep a lot of critters. Substrate is another consideration. Rock, sand, mud, bare ect....If you wanted pods to be plentiful then you would not want a fish that eats them. On the other hand, it would be a good place for a mandarin goby or 2. Plenty to eat without competition. Crabs and snails are a good addition. They can eat and break down stuff so you might not have to as much cleaning to do. Sponges and other filter feeders are another good addition. There are other fuges that are kept in the dark. This is where the other sponges come into play. The more critters you add the more work it can be to make sure they are all getting what they need as far as food and light.

eschaton · Oct 30, 2019

In my old fuge, I didn't introduce anything on purpose other than chaeto. The fuge naturally developed a population of copepods, isopods, amphiopods, mysis, bristleworms, and two different kinds of small brittle stars (a bigger black one which also liked my rockwork, and a small white one which basically just thrived in the fuge). I think there were occasional asterina stars and stomatella snails which also ended up in there - but they had no issue surviving in the main tank either. The coolest random find was a small (like 1 inch in length), translucent squat lobster.

A well-developed chaeto fuge will be so completely packed there really won't be much space except for right at the bottom for livestock of any size to get through. If you treat the fuge more as a secondary display tank though - and have lots of volume to work with - there is more versatility.

Personally, I wouldn't introduce any of the traditional "CUC" members into a fuge. The best way to think about it is that dedicated algae eaters or detrivores basically compete for food with the microfauna that develops in your fuge. Thus even if they don't directly eat the pods, they will cause the overall pod population to drop. I might make an exception for something like a small filter-feeding sea cucumber, but these survive just fine in a main tank.

I would never introduce an adult fish into a fuge. However, if your fish breed, and you aren't prepared to have a dedicated fry tank, it might be worth trapping the fry and dumping them into the fuge, then checking back in a month post-metamorphosis. You might get lucky and get a handful of babies - though the pod population will take awhile to recover again.