Loss of equilibrium treatment success

[jacob2]

Had a situation with my freshwater dwarf puffer come up last night that seems to have resolved, but I thought it might be helpful to others for me to share my experience.

Water params:
pH -> 6.8, give or take testing error
Ammonia -> 0
Nitrite -> 0
Nitrate -> 10 ppm

Standard 10g tank, has been set up in current state for about 9 months. Residents include 4 adult Amano shrimp, each of which has been with this puffer for ~11 months across two tank setups. Also present are 5 rosy loaches (http://seriouslyfish.com/species/yunnanilus-sp-rosy/), a species noticeably shorter than the DP and much smaller overall; they don't notice each other often. Rosy loaches have been in tank for about 3 months.

The filter media were cycled in a fishless cycle of 3-4 weeks prior to the purchase of this DP nearly a year ago.

Water changes: 50% weekly, occasionally as long as 10 days or as little as 4 days between changes. I do a light version of the Estimative Index fertilizer dosing regimen and so keeping up with changes is important to avoid nutrient accumulation.

Feeding: Varies in frequency and type. Bladder snail availability depends on their prevalence in my other tanks, so at times he may receive 1-2 adult bladder snails 5x week but lately I haven't been feeding them. He receives frozen bloodworms 1-2x weekly, frozen spirulina brine shrimp 1-2x weekly, and frozen or freeze-dried mysis shrimp 1-3x weekly. I try to feed at least 4x/week, often more than that. He doesn't accept pellet foods, not that I've spent much of any effort trying to get him to accept those. At one point, live blackworms were a staple but the local supplier has had QC issues of late so he hasn't had them in a few weeks.

Recent changes: Due to a persistent cyanobacteria outbreak that wasn't responding to any of the normal solutions, the tank was in day 2 of a complete blackout—no lights and covered with a dark sheet. I had been taking the sheet off for a few minutes a couple times each day so the fish wouldn't get shocked by the light after the blackout period ended.

So here's what happened:
I removed the sheet to give some food. Here's the first thing I suspected caused the illness but wasn't confident until a bit later. I didn't look too closely at the inhabitants before beginning feeding. I tossed some freeze-dried mysis shrimp in there as I often do. Note that I did not pre-soak. I noticed the puffer track and eat a piece, at which point I diverted my attention elsewhere. A minute later, I saw him following around another piece, and again went about doing something else.

A few minutes later I returned with the intention of covering the tank again but I saw the DP tumbling through the water column! At mid-water I saw him attempt to swim but do a kind of slow-motion barrel roll, clearly lacking equilibrium. I suspected a swim bladder issue until I read on here that puffers don't have those. I suspected that in spite of doing this successfully many times before, this had something to do with not soaking the freeze-dried food. However, I had seen him swim very erratically in the past in response to having the lights turned on after an electrical failure while I was on vacation. While I was sure I saw him grab some food, I wondered if it was related to the blackout.

He continued to do a mixture of swimming poorly with hardly any ability to right himself, making jerking movements towards the bottom, and almost always when looking relatively in control he would have head down, tail up. He would let himself get settled onto plants and rest on them, motionless, something he doesn't normally do. I was extremely upset by this, especially as many minutes passed and there was no change in his behavior.

I also wondered if the cyanobacteria had something to do with it. Water parameters were unexceptional, but I did a 50% change immediately in case the death of cyanobacteria had released something nasty into the water. Still about an hour after the water change, the DP had little ability to do anything but jerk himself around the tank while fighting against the fact that he seemed overly buoyant and was getting pulled to the surface. It was after I saw a rosy loach nip him while resting in a plant that I put him in a .75 gallon specimen container to isolate him and figure out a plan.

Upon reflection, I decided the most probable cause was having the freeze-dried food expand and lodge in his digestive tract. The main thing that went against this explanation was the lack of any noticeable lump, not even the same sort of belly bump he normally gets after a big meal. I checked this forum to make sure that Espom salt would be safe for a dwarf puffer, since I know scaleless fish can be sensitive to this stuff. I dosed it at a concentration equivalent to 1tbsp/10g. I put a short PVC pipe horizontally in the container to give him a place to hide. For the first 20 or so minutes, he lie motionless floating on his side at the top of the water. When I checked on him again and added some more fresh water, he swam poorly around before finally settling in the pipe. No progress over the next hour or so.

I couldn't put him in the tank where the amanos or other fish might stress him to death, but did not like leaving him in an unaerated container for much longer. I needed to sleep, too! I cleaned up and filled up my empty 5g aquarium and put the appropriately tiny HOB filter that I used to use with it on with a Zeolite/carbon mix as media along with a heater set to 76. I acclimated the DP and dosed the epsom and went to bed. I'll note that I had very low expectations at this point. Generally speaking, my assumption and experience is that a fish that lacks equilibrium like this and does a dead man's float like this is rarely brought back to health.

When I woke up and turned on the light, he was floating at the top. But with the light flickering on he jolted and swam around the sparsely decorated isolation tank a bit. I couldn't tell if he was perfectly healthy yet, but he never went belly up which was a positive sign. This afternoon upon arriving home from work, he was swimming around normally, following my finger, etc. I think he's fixed! I plan to put him back in his tank and fast for a couple days tonight.

[Pufferpunk]

Yes, the death of Cyano IS toxic! That is why it's so important to remove as much as possible before treating. It always said on the treatment bottle to do a large WC, within 24 hours after treating.