All fish dying - Need Help!

[Slidecf]

Hi guys,

I could really use some help. Out of nowhere, my fish started dying one by one, a few days apart. Before this started happening, I had neglected the tank's maintenance a little. The aquarium has been running for two years, and every fish that died had been with me since the beginning.

Here's what happened:

A few days ago, my Royal Gramma died. It had what looked like a few white spots and would occasionally scratch itself against the rocks. About a week later, one of my Ocellaris clownfish died. It didn't have any visible white spots, but the night before it died, I noticed it was swimming closer to the surface. I even considered low oxygen levels, although I haven't changed anything in the setup recently that would explain poor oxygenation. It was still eating normally.

Today (five days later), my other Ocellaris died. It had no visible white spots and didn't show any unusual behavior the day before. I actually witnessed it die. It started swimming strangely with its head pointing toward the surface, stayed there for a while, then sank to the bottom of the tank, gasped for a few moments, and died.

I took some photos about 30 minutes after it died (my banded shrimp and hermit crabs had already started scavenging the body). My only remaining fish is a Green Chromis, which has no white spots and appears completely normal—very active and eating well. All of my invertebrates also seem healthy.

Water parameters on the day the Royal Gramma died: Temperature: 27°C (80.6°F) / Salinity: 1.025 / pH: 8.2 / dKH: 10.5 / Calcium: 395 ppm / Magnesium: 1110 ppm / Phosphate: 0.03 ppm / Nitrate: 10 ppm / Ammonia: 0.4 ppm
I know the ammonia wasn't at zero, which isn't ideal, but I don't think 0.4 ppm alone would be enough to kill the fish. After the Royal Gramma died, I performed a 30% water change, and ammonia returned to 0 ppm. The night before my last Ocellaris died, ammonia was also 0 ppm.

I also don't think low oxygen is the issue. I haven't changed anything in the system for quite some time, and these fish had all lived in the tank for the past two years. I run a protein skimmer, and my powerheads provide plenty of surface agitation.

I'm not sure if this is related, but I figured I should mention it. My Green Star Polyps and zoanthids have been looking irritated lately. I've noticed a lot of tiny critters crawling on them, and I'll post some videos to make identification easier. I've also seen different-looking critters on the glass, but they're too small for my camera to focus on, so I can't get any useful footage.

My Setup:

• Tank Size: 40 Gallons
• Salt: Aquaforest ReefSalt
• Light: AquaKnight V3 60W + Solarium Blue
• Skimmer: RedStarfish SQ90-Plus
• Fish: 2 Ocellaris (Dead) / 1 Royal Gramma (Dead) / 1 Green Chromis
• 1 Coral Banded Shrimp / 1 Peppermint Shrimp / Some hermit crabs and turbos

 

[Gumbies R Us]

#fishmedic

 

[BryanM]

I wouldn't be so sure that the ammonia isn't an issue, but I will let more knowledgeable people respond

 

[Mr. Mojo Rising]

those small amazon powerheads don't put out a lot of flow, I have a couple myself to mix water. I would get some stronger flow in there and more surface agitation. There is really not much water movement in your tank IMO.

Not sure what it means to let maintenance go a little, but if you let the water quality degrade, it would stress the fish which might cause disease. If corals are suffering then it kind of leans towards poor water quality.

Personally I find your water too warm. There is no benefit to keeping it so warm, and in fact, bad bacteria's and algae both love warm water.

 

[EnterName]

Ammonia levels of 0.4ppm shouldn't happen in a cycled tank, but also shouldn't cause a massive fish die-off within a few days (see Randy's article "Ammonia is our friend" in which he also cites a study that showed how 50% of the tested false clownfish were able to tolerate 13ppm total ammonia for 4 days).

This still hints towards something being off with the water quality... I can recommend an ICP-MS test to make sure there isn't something in your water that causes issues.

 

[Slidecf]

those small amazon powerheads don't put out a lot of flow, I have a couple myself to mix water. I would get some stronger flow in there and more surface agitation. There is really not much water movement in your tank IMO.

Not sure what it means to let maintenance go a little, but if you let the water quality degrade, it would stress the fish which might cause disease. If corals are suffering then it kind of leans towards poor water quality.

Personally I find your water too warm. There is no benefit to keeping it so warm, and in fact, bad bacteria's and algae both love warm water.

The flow in my tank has always been difficult to dial in. I've tried using higher-flow pumps, but they end up blowing the sand around and creating bare spots everywhere. I also experimented with different pump positions, but either they would still move the sand too much or direct too much flow at the corals, causing them to stay closed or look stressed. Higher-end pumps like gyres are extremely expensive here in my country, so I'm hesitant to invest in one only to find out that I can't use it because of the same issues. At this point, I've just accepted that my tank is going to have a few dead spots with lower flow (but I'm open to any suggestions you might have on how to deal with it.).

That said, I really don't believe insufficient flow or low oxygen is the cause of what's happening. All of these fish lived in this tank for two years, and I haven't made any changes to the flow recently. It just doesn't make sense that they would suddenly start dying because of that now.

Regarding my lack of maintenance, before all of this started I hadn't been doing many water changes for over a month. I was basically just scraping the glass every 7–10 days and replacing the filter pads. Over the last month, I also noticed a significant increase in algae growth on the rocks, and I believe I was dealing with a dinoflagellate outbreak as well, which I'm still trying to get under control. After the first fish died, I started taking more aggressive action. I performed several water changes, manually removed most of the algae from the rocks, filtered out as many dinoflagellates as possible multiple times using a Shark Bag, and intentionally raised my phosphate from 0.03 ppm to 0.06 ppm. At this point, both the dinoflagellate outbreak and the algae problem seem to be largely under control.

 

[Slidecf]

Ammonia levels of 0.4ppm shouldn't happen in a cycled tank, but also shouldn't cause a massive fish die-off within a few days (see Randy's article "Ammonia is our friend" in which he also cites a study that showed how 50% of the tested false clownfish were able to tolerate 13ppm total ammonia for 4 days).

This still hints towards something being off with the water quality... I can recommend an ICP-MS test to make sure there isn't something in your water that causes issues.

Yeah, I don't think ammonia was the problem either, especially since I performed a water change after the first fish died and brought the ammonia back down to 0 ppm. My last fish survived for almost 15 more days after that, so it spent those two weeks in water with no detectable ammonia.
I'm afraid it might be some kind of disease that's killing them. I have a feeling my Royal Gramma had two or three white spots and was occasionally scratching against the rocks, but nothing excessive. It also stopped eating the day before it died, which makes me think something was already wrong. Oddly enough, neither of the Ocellaris clownfish showed many signs of disease or unusual behavior like the Royal Gramma did. Aside from the symptoms shortly before they died, they appeared completely normal.

As for an ICP test, I'm not sure how accessible or affordable it is where I live, but I'll look into it. If it's an option, I'll definitely have one done.