I've had a few fish deaths recently and I'm worried about it. Here's all the details:
for now. Cycled using pure ammonia in November 2009. There's a 20G sump and a 20G refugium for a total of about 180G in the system. There are about 250 pounds of LR
in the system that I use for biological filtration. Also, a month or so ago I added a Tunze protein skimmer into the sump which seems to be working OK. If you need more details, there's a link in my signature to my fish blog, and the "tank specs" page contains a bunch of information.
Before - 5 damsels, 3 tangs, 4 Bangai Cardinals, 1 Cave Goby, 1 firefish goby, 1 bi-color blenny, 1 mandarin, 20 or so Nassarius snails, 1 Royal Gramma.
Over the past 6 months the cardinals have gone from 4 to 2. I can't be exactly sure when, since when they breed it's typical for them to hide on the rocks for a few weeks without me seeing them at all. Their behavior during this time can be pretty aggressive, so I chalked these up to aggression.
From March 9-15 I went on vacation. When I came back, I couldn't find the Bi-color Blenny. Since then, I've lost the Firefish Goby, the mandarin, the cave goby, and possibly the Royal Gramma. I haven't noticed any signs of sickness or anything from any of these fish, but I haven't been around my tank nearly as much as I should recently because of all the travel.
What's been going on:
I'll start with measurements that I took last night:
Specific Gravity: about 1.023 (refractometer)
Temperature: 80-90F (more explanation below)
Nitrate: about 200 ppm
So the red flags are temperature and nitrates, obviously. I should explain what's going on here. Over the past few weeks I had slacked on making my water changes. I eventually wanted to get my nitrates down to zero, so when I got back from vacation (last weekend) I put together about 60 gallons for a large water change -- this would be the first of many water changes.
Unfortunately, one of my trash cans failed and dumped 40 gallons of saltwater on my carpet/laminate floor. This sucks, but my homeowner's insurance covers it. So, no water change yet, but instead I've had fans and dehumidifiers running in my house for about a week (they are gone as of last night). The temperature in that room was about 95 degrees during that time. Between the unseasonably warm weather and one of my heaters which I suspect is going crazy (and is now unplugged), the temperature has been fluctuating between 80 and 90 degrees over the past couple of weeks. It's possible that this could be part of the problem.
Also, because of the increased temp. I've been topping off the tank a lot more than normal recently, which means possible fluctuations in Specific Gravity (though I can't see it being that significant). I try to keep it between 1.023 and 1.025 at all times, and that measurement (1.023) was made after a top-off of maybe 5 gallons (I had to travel for work this week. I got back last night and topped it off (and found some dead fish)).
So, nitrates, temperature/SG
are the suspect things here.
There's one other issue that I don't think is related, but it might be. Two of the tangs have been sort of recently competing for dominance. It looks like they got in a bit of a fight while I was gone, and one of them (Buzz) looks like he got the worse end of things. He's acting like he just got put in his place, and it looks like he just got beat up a bit, but I didn't want to rule out that it's related to the rest of the problems. The best picture I could get is here:
It's not the best picture in the world, and he really doesn't want to show me his other side, which looks a bit worse. If this is aggression then I'll feel better, but if this is a disease, then he's the only one with symptoms.
Could all this be explained by temperature/nitrates/aggression? Or is there something else that could be wrong here? I really don't want the answer to be "start from scratch", but I'm afraid that it is. Any help or ideas would be appreciated. Thanks.