Mystery parasite help please

[LallyBiggles]

Hi
please help with these parasites. I thought they were the parasite that causes hole in the head. I have treated the whole tank with metronidazol (api general cure) which seemed to slow it down a bit maybe but didn't get rid of it. Switched to octozin. Which has active ingredient dimetridazol for 2 weeks again seemed to slow it possibly until today when they've definatly spread on the fish in question. Fish is still active and well. This tank has been set up for 3 years. Its 330l bare bottomed running with an oversized oasie canister filter, haven't had a ammonia or nitrite reading for years. Any help much appreciated this has been going on for 4 weeks now and I am out of ideas.

[chelltom]

May sound simple but have you tried dosing with aquarium salt . Sometimes the simple things work the best especially for external issues .

[danotaylor]

What is your nitrate reading? Discus develop pimples that erupt and appear like the pic you posted. Nitrates consistently >10 can lead to discus pimples. I had the same issues when I kept discus in 2018-19. Salt as suggested helped but increasing my water changes to keep the nitrate <10 on water change day was what fixed the issue.
when we moved to our current home in 2020 I discovered that our source water had nitrates at 10ppm right out of the tap, so I no longer keep discus.
All the best

[brewmaster15]

Discus can definitely get "pimples" from poor water quality. Thet usually resolve on their own with improved water quality. They may rupture and leave a small hole that heals. Sometimes though these pimples can be the start of a serious bacterial infection thought to be caused by Aeromonas .spp. Metro and dimetro have limited effect on bacterial infections working predominantly on protozoans and anaerobic bacteria. Have these pimples ruptured at all?

As a side question ..have you ever dewormed them? what do you feed? Any new additions in the last few months?
al

[LallyBiggles]

No new additions for years. API generalcure has praziquantil in it, as well as metronidazol so yes they've for sure been wormed as part of my efforts to get rid of this thing.

I buy a white fish based beef heart alternative from my local breeder that he makes himself, have done for years with no issue so far, they also get bug bites. Doesn't look like pimples to me looks like a little white things attached to the skin. They dont rupture they just dissapear and then reappear in a new place. I was excited about the nitrate theory because my husband recently has been feeding them and I thought he might have been overfeeding, and it's a test I dont often bother with all about ph etc in my soft water. But nope everything looks fine regarding water quality to me.
ph 6.8
Kh 2deg
nitrate about 3ppm
Ammonia and nitrite both at 0

[Second Hand Pat]

Hi, how are you measuring your nitrates? If using the API nitrate test be sure to following the directions exactly.
Pat

[brewmaster15]

No new additions for years. API generalcure has praziquantil in it, as well as metronidazol so yes they've for sure been wormed as part of my efforts to get rid of this thing.

I buy a white fish based beef heart alternative from my local breeder that he makes himself, have done for years with no issue so far, they also get bug bites. Doesn't look like pimples to me looks like a little white things attached to the skin. They dont rupture they just dissapear and then reappear in a new place. I was excited about the nitrate theory because my husband recently has been feeding them and I thought he might have been overfeeding, and it's a test I dont often bother with all about ph etc in my soft water. But nope everything looks fine regarding water quality to me.
ph 6.8
Kh 2deg
nitrate about 3ppm
Ammonia and nitrite both at 0

Thanks for the info. Ok so first up the deworming.. prazi is actually not a great dewormer except for gill flukes and tapeworms and maybe effective against capillaria.Its not as broad spectrum as Levamisole. So that may be something to consider.

Unless your fishfood supplier cooks that whitefish there is always the chance of worms and parasites, from eggs,cystes etc.

My suggestion here would be to try a salt bath or dip on affected fish. A bath of 1 tablespoon tablesalt per 1 gal water is safe and effective for many external parasites..Run that for a week.
Most fish are ok with it but some plecos and catfish maynot. If you have these use half strength at first. Plants may not be happy either. A salt dip is highly effective but often stressful for the hobbyist .

[LallyBiggles]

Thank you very much for the ideas. I will salt the tank I think and try Levamisole. I have a plant in there which is easily removed and popped in a bucket with air temporarily. I will provide an update to let future forum user know if it works!