Adding CUC and a fish in a cycled tank


New member
I reset my tank about 2 weeks ago.
During the moving I kept the live rock(60 lb) in bins with water and a pump in order to keep the bacteria alive.
The sandbed was completely removed. BB at the moment. New water was added in the tank. Out of 70 gallons about10 gallons were introduced from the previous setup.

So at the moment the tank is up and running, sump, skimmer, heater, chiller all setup.(ATO and ATS on the way)

I have a small clownfish(amphiprion ocellaris) in there that was in the tank before the moving.

Tomorrow I plan on getting aragonite sand to add as a sandbed. I will be washing the sand with RO/DI water and after cleaning I will be using a tube to get the sand in the bottom of the tank to avoid disturbing the clownfish and some collonista snails and tubeworms.

I also plan on to add part of the clean up crew.
For a start I don't want to add too much bioload at once since there is only one fish in there.
2 or 3 hermit crabs(small), or 2 large ones(does the hermit size matter?)
2-3 turbo snails
and a shrimp(cleaner or fire, any advice on which is more hardy and easier to care for).
I also want to add another clownfish to make a pair.

Would the above be too much of a bioload to add in a 75 gallon that is already cycled?

Also is there any incompatibility with the above?
My future plans include a diamond goby.

After that I will try my luck with a few polyps and soft corals.
And further down the road maybe depending on how hardy or peaceful these fish are:
bangai cardinal(pair)
royal gramma

If any of the above are hard to care for or incompatible please advice.


New member
Add the sand, and let it settle for a day or two before adding any more livestock.

After that, the list you provided looks just fine, although you will want to get 2-3 dozen hermits, and 2-3 dozen snails, 6 inverts in a 75 Gal won't be nearly enough to keep up with the tank. Wait on the shrimp for another few months, they need a stable tank, elevated nitrate and salinity fluctuation will lead to their early demise.

As for the fish, adding another clown may or may not work, but the cardinal's, and diamond goby will be just fine. Add the royal gamma last, as they can be touchy when protecting their claim. Clowns can pair, but they can also fight to the death. If you're hoping they pair, it may just be easier to buy a pair, or two juveniles from the same tank.


Team RC
+1 on letting the sand settle for a couple of days before additional livestock. I don't think I would add as many hermit crabs as Chris suggests, ultimately 15 - 20 should be fine, but add them slowly as the tank matures (start with 5-10). I would eventually get to around 30 assorted snails, but again start with 10 or so.