Zoas dying. Others taking over.....

[Squatch XXL]

I've had my 40 breeder tank setup for almost a year at my current residence.

Since the move, I have had great success with SPS corals. My zoas, no matter where I put them never seem to advance. Back when the tank was new, they grew like crazy. Eventually, they all have disappeared away. This has been happening since the beginning of the year, and affects new and old frags. High to low flow placement of a few colonies, near and far from the lights. My small colony of palys acts the same, but does not seem to ever die off.

Monti, Acro, pocci and protopaly do quite well. Cyphestra is almost a nuisance and growing well.

Lighting is a simple quad t5 36", and has never changed. Weekly water changes of 5 gal. I top off with a drip from a 5 gallon gravity ato. Nitrates are never over 10 ppm.

I have 1 small wrasse and a small efficient clean up crew. I feed a 3-4 times a week a mix of frozen brine and other things in a slurry. Selcon is target fed and broadcast fed. There is nothing left of the frozen food within 20 minutes.

 

[DaveK]

There are a few things you should check. First off, your about due for a light bulb change, so you should do that. It's amazing how much less light is produced and how much the color spectrum shifts over a year.

Next check your water parameters. One or more may be off.

Zoas are a little different compared to SPS. Zoas tend to like calmer water, less light and sometimes water that is not so clean. You may want to try them in dim areas of your tank.

Look for fish or other livestock that may be bothering or even eating your Zoas. Yea, I know no fish are supposed to eat Zoas, but I one had a batfish, Platax sp., eat a couple of large zoa colonies I had.

Lastly, sometimes no matter how good the tank seems to be, it just will not grow some corals. If that seems to be the case, replace the coral or zoa with something that does well in your system.

 

[Blue Space]

If you think you water is lacking nutrients your coral need then try using reef chili coral food and see if that makes a difference.

 

[Squatch XXL]

due for a light bulb change

Zoas tend to like calmer water, less light and sometimes water that is not so clean. You may want to try them in dim areas of your tank.

Look for fish or other livestock that may be bothering or even eating your Zoas.

Lastly, sometimes no matter how good the tank seems to be, it just will not grow some corals.

Great points @DaveK

The bulbs were changed 3 weeks ago. This problem with them not advancing or growing is not recent. Since the tank has only ever had 1 critter in it at a time, I am very light on feeding. When the mantis shrimp died in January, I stopped feeding the tank for almost 2 months and everything but the zoas seemed to respond well. I still changed water and did maintain, but simply did not add any food.

I do feed 3-4 times a week not that I have a fish.....what I consider a lot of food, and only house a small wrasse. There is never anything left after 20 minutes. My CUC is kept trim, and slightly hungry to make them appreciate it more. The hermits can and do eat snails regular.

Back when the tank was new there was no trouble with zoas spreading out, so I fragged more than a few and now have them all over. I try shade, low flow and nothing. I try high flow, and in shade etc. I have a "Darth Maul Porites" growing out over the plug in the shade of an overhang near a zoa that recently just disappeared.

There was an incident involving Nudibranch last September, and the infestation was removed with time, a q-tank and some bayer advanced bug killer. I have not seen a living nudibranch since I added them back in 11-2015. I have one other frag of zoas that I just watched literally shrink up and disappear over a few few weeks.

I have a very active hermit population, and they do crawl all over the corals....But not once have I seen them actually picking at a polyp to eat it.

The only reason I have a fish at all is because it will eat nudibranch should they ever reemerge. I am very particular about q-tanking now, and also very particular at who I buy coral from. When comes to reef keeping, abstinence from coral purchase is the only way to keep from going insane. I usually find a swap every 6 months to a year, and blow a few bucks knowing I can q-tank and dip everything.

I do think it is possible at this point, that certain species just won't grow. I have a shallow tank, the lights are close and they are bright. It is just some generic single reflector quad t5. Years ago I had a 75 with a pair of 400w MH, and had the same problem. I could not get a zoa to grow...but I got sick of porites growing everywhere.

If you think you water is lacking nutrients your coral need then try using reef chili coral food and see if that makes a difference.

I am going to check that out. I have been adding Selcon at feeding time 75ml mixed in at least 2 full shot glasses of tank water. The proto-paly population reacts to target feedings, but the zoas and pallys don't. My concern is that would creating conditions for one type, adversely effect my other corals?

I have a second tank that is a few weeks from being done curing. Id rather my zoas went there to die if that is what they are going to do. There aren't many left, and one colony is on a really nice old dead acro frag. I could use the rock if they don't.


I had a basic water check @ my LFS

0 ammonia
0 nitrite
detectable nitrate less than 10ppm. 10ppm is the first color or something on his kit.

I used my only test kit at the house.

460 ppm calc

I was overdue for the weekly 5g water change by 2 weeks, so that explains why there were nitrates detected. I may switch to 10g bi-weekly so it is easier to fit my schedule.

In the past 2 months I introduced a DIY ato of a gravity controlled 5 gallon. I add 1 spoon of pickling lime to 5 gallons of water. It is probably not necessary, but I have seen noticeable growth on a monti cap only after adding this part. 6 months it just sat there, and moved slow. In the past 2 it just blew up.