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Help me figure out why my cuttle died...

Jun 16, 2005
I've got 4 sepia officianalis cuttles, a 900 gallon system. They were all doing fine yesterday, however one did not eat this morning, this afternoon he bagan holding his tentacles splayed out, then later his feeding tentacles began dangling and he died shortly. They have been here about 3-4 months and doing fine, however out of the blue a couple weeks ago, I had a nitrite spike, but was doing water changes almost every day. The nitrites yesterday were 0.169 and today were down to 0.158. Still not sure where the nitrites are coming from as they get water changes at least once a week regularly. When the nitrites spiked the water changes began every day or other day. They have all been acting normally despite high chems until today.....any ideas?
Have you checked your silicate levels? Holding the tentacles splayed out sounds like a oxygen transfer issue...how are your water temps?


I think stressing is always a possibility, however I can't imagine what would have stressed just one and not the other three, especially when nothing has changed in the system in the past month at least other than the nitrites. Temps are sitting around 76 most days, but occasionally fluctuate to 78. I was however misinformed and they are not officianalis, but are pharaonis instead. This led me to question that perhaps they are simply getting older and their coping abilities are on the decline...who knows.....have not checked silicate levels, however the only water going into the system ever has been salted RODI.
If there's not enough oxygen for the cuttle it wouldn't be able to control its muscles hence the tentacle splaying. But I don't thats the problem cause it would affect the other cuttles too.

Pharoanis have pretty short lifespans, around 8 or 9 months I've heard, so if your cuttle is rather large then old age would be a possibility.

well, thank you all for the input, I think I've pretty much settled on a combination of old age and the nitrite issue. However, the nitrite issue is still a mystery,it's down to 0.136 after almost three weeks of water changes, no end in sight so far. I think that the bio tower has gotten detritus accumulated in it perhaps creating anozic zones?....ever happen to anyone before? Otherwise I can't figure it out..
Well, that would certainly lead to water impurities...what a mess to clean up though !

Quite a mess to not only clean up but do at all. I suppose I will have to break the thing down and try to rinse the bio balls and maybe vaccuum the bio tower itself...wow what a pain. However on the up side the other three cuttles seem fine and are eating happily so....now to cleaning ...:smile:
On the nitrite issue...

Do you test your nitrate reading? Is it getting lower?

If your trickle tower/filter is getting blocked then in all likelihood what is happening is the lack of oxygen in the filter is causing bacteria to convert the nitrate BACK into nitrite!

You'll certainly need to strip down the filter and clean the balls... Make sure you put in a very good prefilter of fine wool or even better have the water from the tank go through the skimmer first and then into the filter via a micron bag.
The nitrates have been going up, although they are currently being tested only weekly....although now that you mention it I will definitely have to look into that possibility more thouroughly. The system is set up with a 200 gallon sump below the display tank and a 6 foot tall bio tower full of bio balls...it is not however set up as a trickle filter, from the bio tower it moves to a huge RK skimmer, I don't know what model, but it's bigger than I am. LOL. When the nitrites first became an issue I put some filter floss in the skimmer boxes on either side so that water from the tank would hit those before getting to the sump, the nitrite readings have been steady for a week know at 0.139, despite the floss, and still getting 100 gallon or so water changes daily..there is no actual source of oxygen in the bio tower, I suppose the design relies on the water being oxygenated in the sump or on its way out of the tank. Any ideas Colin?
yep :smile:

first thing is to try and set it up so that the water enters the skimmer as soon as it leaves the tank. That way the bubbles will help oxygenate the water straight away. Then have the water go through into the biotower via a filterfloss mat. Skimmers are one of the most effective ways to remove wastes and oxygenate water. It is a waste of a skimmer to have the water go through a tower first as it can remove a lot of waste before the tower needs to try.

The water should drip or spray evenly over the biomedia and flow over as much of it as possible.

A good way to increase air in the tower is to have an air pump pumping in air via an airline into the bottom of the tower. This helps oxygenate the tower and stops stale air settling anywhere.

Which test kits are you using and be award that kits have a shelf life of about 6 months after opening and therefore cant be trusted

hope this helps

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