How much salt is too much salt?

[Sasha]

I have a single 5 inch Red Scribbelt discus in a 10 gallon quarantine tank. He's eating well and acting normal other than occasionally turning dark and flashing against the filter box that hangs into the tank. He has a slight greyish hue on his skin, a spot smaller than a penny,located just under the fin that runs along the top of his body. The greyish hue is only seen when he turns in a certain direction (I can't see it when I have a full side view of the fish). He also occasionally has some fine, translucent thread-like strings that drift off of his body. One of two of these almost mucous like strings can be seen floating freely through the water column. It's almost as if he is shedding off some of his slime coat, which seems to congeal into these translucent strings.

I recently got a microscope and did a skin scraping and a gill scraping. While I'm new at evaluating the slides, I did not see much of anything moving in those scrapes. However, when I scoped one of the translucent strings, I saw a couple varieties of ciliates, albeit in very low numbers. One ciliate I was able to identify as Euplotes. I have also witnessed what I think is Tetrahymena when I scoped tank detrius.

I administered QuickCure according to the package directions, and I have seen some improvement (improved color, fewer periods of turning dark, and lessened frequency of flashing). However, he is still flashing, and I have the issue of the occasional, floating string like material.

I'd like to move him back into the main tank as soon as possible, but want to address the issue of the flashing. Since the QuickCure was only partially effective, and because it messes with the biological system, I am thinking of using a salt treatment.

I prefer not to do a salt bath due to the significant stress it puts on the fish. And, since the ciliates appear to also be floating in the water in these strings, I'd like to treat the whole tank.

Some research indicates that a 0.2% salt solution can be used over the course of several hours as a full tank treatment. I believe that is approx 6 and 2/3rd Tablespoons of salt for 10 gallons of water. That's a lot of salt.

Question: can Discus tolerate that amount of salt? And for how long should I keep that level of salt in the tank before reducing it via water changes?

Parameters:
- well water, aged and heated, PH 8.1
- Ammonia - less than 0.25 ppm (slight spike due to the QuickCure causing mini cycle)
- Nitrites - zero
- Nitrates - 10 ppm

Thank you.

[jimg]

I do salt dips at 3%. 7.5 tbs per gal. put them in until they roll over or ten minutes.
some will lay on their sides, when you push them the will upright again, if you see them not up righting again or curling take them out. I usually get about 5-7 minutes before they really stress. you have to be careful and watch them. I do this 1x every day for 3 days. then into clean tank.
how long did you do qc?

[Sasha]

Thanks for your quick reply. Call me a softie, but I hate to put my guy thru that much stress. That's why I was leaning towards a longer term immersion in the tank that would hopefully be less stressful on the fish yet still get the job done.

And, if I do the salt bath as you indicate, isn't there greater likelihood of re-infestation from the ciliates that are in the water column still in the tank? I understand you recommend the 3 dips to potentially combat the re-infestation.

Boy, I hate to torture him like that. But maybe it's a case of needing to apply show tough love.

[Sasha]

how long did you do qc?

He went thru a 21 day period of QuickCure (dosed every other day with 50%+ water changes on the "off days"). That course of treatment finished about 3 weeks ago. I thought I was all set and was just about to reintroduce him to the main tank again when this new bout cropped up.

[Discus Origins]

I've gone up to 3 tablespoon/5 gallon concentration for 7 days with no ill effects. Was very effective with slime coat and fungal problems.

[jimg]

If you did 21 days with qc which Imo is way too long then I doubt parasites are the culprit. I have done 2 tbs per 10 for up to 3 days but do not like it that much that long either. the 3% salt dip ime is the way I like, you can also do pp at 2ppm for 4-5 hrs if you have it then into a qt with furan 2 or similar anti bio.
If you want, I would suggest this since it could use a break from treatments,for a longer term bath in the main tank I would do 1 tbs per 10 for a week max.
Double check all water parameters incl ph gh make sure the water is not irritating the fish.