Please help me with new Dendrophyllia!

Costas Soler

New member
Hello!
About two months ago I started cycling a 5-gallon nano tank in my college bedroom. It's not my first saltwater tank but (been reef keeping for about 6 years now), but it is my first nano. Last week, I added my first Dendrophyllia - a single polyp of a "sunburst skittle" dendro. The plan for this tank is to be a Dendrophyllia biotope tank, and I know how easily nps inhabitants can foul the water with frequent feedings, so I'm not planning on adding any other inhabitants. This dendro is my top priority! The tank has no filtration; just a 600gph powerhead and weekly water changes of 1 gallon (with rocks and sand the tank contains about 3.5 gallons). The only lights on the tank are an array of dim, blue LED's that I built. These are just so I can see the coral under some realistic lighting, and I have no intention of growing anything with those btw.

The specific gravity has been 1.026-1.027 this week, Calcium has been 380ppm, and nitrates and phosphates have been around 0. I'm supplimenting with 1 ml each of Kent Marine Nano Reef Part A and B.

After adding the dendro to the tank in an area of medium flow, the dendro was a bit shy and remained half-closed. A few hours after arrival and acclimation, I fed it a small piece of grocery store-bought shrimp (the piece was about the size of the polyp's mouth). After that, the polyp extended it's tentacles and appeared pretty happy for the next few days. Two days later (Saturday), I fed it some Coral Frenzy 0.5mm pellets, and not much changed. On Monday though, he started to retract his tentacles, and remained closed throughout part of the day, only extending about halfway later in the day. I changed some water, worried that it could be a build up of phosphates or ammonia from the food and waste, but he just remained in that state.

After testing the water for phosphates and nitrates and finding good conditions, I thought it might be the relatively high flow. I then moved him to another part of the tank with lower flow, and still no improvement. Yesterday I planted a piece of plastic in the sand in front of him as a sort of windscreen for the flow, but still no improvement.

I may be wrong, but I don't think the flow is the problem here. Last week, the polyp was in an area of way higher flow, and it opened fully all day and all night.

I've continued feeding him, and he is eating. His tentacles are a bit more extended, and he is still eating, but the tentacles look sickly and a bit deflated. Also, the polyp's mouth is gaping as of today, which doesn't look good :( I'll change the water again tomorrow. If you have any ideas to help me return him to his beautiful happy self (like you can see in the first picture, taken last Friday) I'd be very grateful!

Thanks a lot!!!

I've included a picture of the polyp fully extended from last week, a picture when it started to remain closed, as well as a picture from just now and a full tank shot for reference.
 
Here are the photos!
 

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I have a 55 gallon NPS tank which includes several colonies of dendros as well as many rhizos, tubastrea, balano, monomyces and other nps corals.
I agree about over feeding. Also, and I can’t say for certain that this may or may not be an issue, and I know many people do it, but I don’t use human food. Sometimes the pieces are too big, sometimes they may be bacteria carriers which could affect your system.
I feed mysis shrimp and Larry’s Reef Frenzy mixed with some frozen calanus to my system. The pieces are tiny. I don’t target feed, but as you have a dedicated small tank for this one Coral right now, you could consider using a pipette to keep the food near the coral.
Don’t ‘push’ the food into the mouth, just let the tentacles grab it.
Get a small Pederson’s shrimp or something to clean up extra food, too (bumblebee shrimp are good, too). Yes, it might try to steal food from the coral, but if the pieces are small enough, this won’t be an issue.
I feed my system 2 to 5 times a day, depending on what is happening and how much time I have.
And yes, they do have days they pout and may not extend tentacles.
 
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