Bloat - Salt didn't help

[Demosthenes]

Problem

1. Please explain the problems with your fish. When did you notice the problems and did anything unusual happen that you think started them?
Last week I noticed my discus breathing heavily and had inflamed gills. I discovered a coating of pink slime and white fungus/mold on the inside of my canister filter. I cleaned the filter thoroughly, added an air stone, and treated the tank with salt at 1tbs/10gal. Heavy breathing subsided and the gills seemed to be improving. 3 days later I opened the canister again and again found a coating of moldy looking slime, again cleaned it out and then added a pre-filter sponge to the canister intake. Then on Saturday one fish abruptly bloated and passed within 24hrs. Increasing salt concentration to 1tbs/5gal did not help. I tried adding Kanaplex but the fish was gone within 2 hrs of adding it, so I did a water change to remove the meds. This occurred on Sunday. Now I am looking at my tank and there is one fish who is possibly in the early stages of bloating - not sure yet. I haven't fed them in 4 hrs and he looks like he has a full belly. No other symptoms as of yet.

2. Symptoms (i.e. turning dark, excess slime, not eating, clamped fins, flashing, darting, clamped gills, white/yellow/green poop, hiding, headstanding or tailstanding, white on tips of fins, rotting or fungus, blisters/white zits on fish, bloated, cloudy eyes, wounds).
Heavy breathing, inflamed gills, one fish bloated and passed yesterday, another fish seems to be starting to bloat now.

3. What medications/ treatments have you already tried and what were the results. Include dosage and duration of treatment.
Salt at 1tbs/10gal has been in the tank for the past 5 days. Improved gill symptoms but ineffective against bloat. Kanaplex was in the tank Sunday morning but only for 2 or 3 hrs before being removed so I can't speak to its effects. I will say it seemed to stress out the other healthy fish, but didn't save the bloated one.


Tank/Water

4. Tank size and ages, numbers and sizes of fish.
37gal, fish purchased from Hans at 3 inches 3wks ago, there were 7 but now 6


5. Water change regime (What percentage and how often).
95% daily

6. How long has tank been running? Is it bare bottom? If you have substrate, what type and how deep is it?
Tank is a 40gal breeder. Has been running for 10+ yrs with current filter, but recently stripped to bare-bottom to be used as grow-out tank.

7. Do you age your water? If you do for how long and what is the ph swing.
No aging, no swing.

8. Parameters and water source;

Note: Water Parameters are important in diagnosing problems within a tank. If you don't own test kits for the following information, you can purchase them, test your parameters and post this info as soon as possible.


- temp __85_

- ph __6.7_

- ammonia reading __Not sure - I haven't tested for ammonia in yrs since the tank has been cycled forever and it isn't on my test strips. I added some Prime to be safe.__

- nitrite reading __0__

- nitrate reading __barely registers__

What type of water or combinations of water sources do you use? If it is an RO/tap/well water mix, please list percentages in the mix.

- well water ____

- municipal water __X_

- RO water ____


9. Any new fish, plants or inverts added recently.
All discus added 3 wks ago. There are no other current occupants, but the tank was previously used as a community tank and not sterilized in between. All previous occupants had been in the tank for more than 2 yrs.

10. Please tell us what you feed your fish and how often. This can be critical information for solving the problem so be as specific as you can.
Hans' beef heart mix 2 or 3 x daily, plus occasional Tetra Color Bits

11. Include any pictures or videos you have which shows the symptoms. If you can't add them to this post, please provide a link to them.
lights are out for now, will post photo in the morning

[Demosthenes]

I'm almost certain that this is an infection being caused by rotting beef heart in the canister filter. Whatever the white mold/fungus/bacteria stuff that was growing in there is getting to the fish. If this fish still looks bloated in the morning I'm thinking I'll dose the tank with Kanaplex. Is there a better choice? I'll need to move fast since the last fish to bloat was gone in 20hrs.

[Demosthenes]

**UPDATE - I just saw the possibly bloating fish poop. It looked normal enough. Small, brown. So no blockage, but still not clearing food as fast as he should be. Will update again in the morning.**

[Demosthenes]

Ok the fish in question seems to have recovered overnight. But I'm feeling far from confident that I've solved my problems. My plan was to add a sponge filter and run it alongside the canister for a few weeks to let it get seeded, before removing the canister with it's mystery mold. But now seeing how these fish are apparently seconds from disaster at any moment, I'm wondering if I need to be more aggressive. Anyone have any ideas? If I deep clean the filter media every three days I'm going to kill all my BB. Salt seems to be very tenuously helping, but not curing. Should I be trying to medicate the tank to kill off whatever this fungus/bacteria/mold stuff is?