Thank you Michael!
I was thinking about the health of my tank last night. My fish seem to thrive even though it's a small tank. I have 11 fish that are between 3 and 5" long. They're all fat and breeding. When I caught all my fish, they averaged and inch long, and grew to adult size in about 8 months. I've had this tank set up for two years now. I began with 7 striped blennies, 5 skilletfish, and 5 naked gobies. I now have 4 striped blennies, 2 skilletfish, and 4 naked gobies.
How I lost fish:
Blennies - One adult female blenny jumped out of the tank after my disease outbreak while being treated in QT. The other blenny lost was a male that jumped out of my DT a couple weeks ago. I had one adult male blenny die after going blind about 6 months ago.
Skilletfish - Two adults died of disease during the outbreak, one just went missing this week (it was the one that wasn't eating). I assume it was an internal parasite.
Naked gobies - I lost one a few months ago, unknown, found dead but seemed healthy until then.
I haven't been testing my parameters in months. I got lazy, so last night, I tested for ammonia (zero), nitrite (zero), nitrate (50). I thought that if a fish was missing and died, that the levels would have been elevated, but not, so I was surprised by that.
Invertebrates in both tanks:
Ghost anemones - I had three in my DT and thrived until I returned my fish from QT, then they disappeared. I had three in my invert tank, and one is huge and thriving. The others could be alive somewhere in the oyster cultch. They move around a lot and are hard to see, but I haven't seen them in a month or so.
Tunicates - I had them in both tanks. They live about 6 months as adults then die off. Every now and then, I'll find one inside an oyster shell, but haven't seen any in a while now (about three months). There could be some deep in the cultches, but I may have killed them when I pulled the reef apart for repair, because the reef was dry for a few days.
Barnacles - Some died that I collected, but, I still have a few (2 different species) that have lived for over a year now and are doing well. I think that once they survive the early stages of captivity, some adapt and do well if fed properly.
Mussels - Same as barnacles, I've collected and kept about a dozen of them between the two tanks, but most have died off. I still have four alive that seem to be doing well that are a year old now.
Grass Shrimp - I've been able to keep them in the DT with the fish for about 6 months, then they gradually disappear. Some jump out of the tank, and I think the fish killed and ate some too. In my invert tank, they can't get out, and have lived over a year now. I started with about 30, and there are about 20 left, but, they're hard to count because they move around a lot, and hide throughout the reef. So, there could still be 30 in there.
Mud Crabs - I've kept two different species. In my DT, I didn't find any when I pulled out the reef, but, there could still be some in the tank. They hide in the reef and also bury themselves, and I really didn't look for them. Some may have died or crawled away when I pulled the reef out of the tank. I haven't found any on the floor though. In my invert tank, there are 6 mud crabs, at least, that I see now and then.
Bristle worms - They are doing well in both tanks. I see them out all the time in my invert tank, but never come out in the fish tank. I see them burrowing around the glass in the sand though, so they're there. I think that they only come out at night.
Amphipods - The fish ate all of them in the DT, but some are still alive in my invert tank. I see them now and then feeding on algae on the glass. They're nocturnal, and very wary, and hide all the time.
Copepods - I had a bunch that I always saw on the glass, but since I used Prazipro, I haven't seen any lately. It might be because I cleaned the glass, but I used to see a few even then. The glass is starting to get algae again, and is due a cleaning, but I think I'll wait and see if any pods appear. I never see any in the invert tank, because I think that the anemones eat them. I'm sure that some are living in there though.
Snails - I found one lone micro sized snail living in my DT when my fish were in QT. But, I haven't seen it since the fish were returned. The fish may have eaten it.
One possible thing that could have happened is that maybe some of the inverts that died off in my DT when I returned my fish from QT, could have been due to elevated ammonia. I did water changes during that time and tested, and there was some ammonia and nitrite present, prior to the water changes. That could have caused the die off rather than the fish eating them. I don't think it would have affected the grass shrimp, but the anemones and snail could have been victims due to that.
So, the question, in my mind, is, will some of these inverts survive with adult fish or are the fish killing them? Ultimately, I'd like to keep the whole cast of characters, a true biotope. We will see.