Best treatment for fish flashing

HI everyone so need your help again so about 1 week ago I noticed 1 or 2 fish were flashing/glancing every now and again , now my tank had suffered a lot recently I had green water to the point where you couldn't see the fish so I brought a uv filter sterilizer it worked made my water crystal clear in 3 days . I carried on doing my 10% water changes once a week, 1 week later fish were flashing and I was having trouble building my tank to what I wanted so I brought a load of stuff to be able to empty my tank , I changed mt sand to fine gravel I saved so e water but mostly did a 75% water change, but as I was emptying my tank when I got to removing sand the side where the uv filter had been was terrible underneath was green rotten egg smelling sand , so at this point I had thought this must be the reason for flashing as a week had past and no white spots, I had ich twice not with the fish I have now but previously other then 2 peppered corys that had ich in another tank and where treated and cleared . and now are in my community tank, so day after I emptied tank and filled it back the fish where not flashing I thought ok I fixed it must of been the sand , but sure enough day 2 some of the fish were flashing and it looked like some tetras were twitching , so I took some tank water went to my local aquatic centre and had it tested , they said everything was good other then nitrate being a little high they said do a water changed I told them well no because yesterday I did 75% water changed , when I told then about my fish they right away told me early signs of ich I told them no ive had this twice its been a week no spots and that ive seen fish with ich they constantly flash mine where doing every now again but still to often so they said to put my heat up to 78f so ive slowly increased the heat right now it 77.7f I haven't seen a lot of flashing but I know something is not right tetras seem twitchy still mainly glow light tetras I'm at a standstill as to what is going on need some help!

1 more thing my corys had breed 2 days before flashing it couldn't have anything to do with that could it. eggs are hatched and today they are free swimming. should be worried about them?

Definitely ICH ... It begins with the flashing and twitchingEven before you notice ich on the fish.

In my experience they flash and twitch before the white spots appear .

ok the only reason I was so against it being ick as its been a week and no noticeable white spots.can they take this long to appear?to me it doesn't seem like ich I will post a short video so maybe you could see

ok so there not flashing at the moment but maybe you guys can see something I don't?

Just because a fish is flashing does not mean it has ich, or that anything is wrong with it for that matter.

yeh I understand what your saying but if was once a twice a week I wouldn't worry but its happening way to often and I watch my tank daily something doesn't seem right I may well be over thinking and paranoid I hope this is this case lol

Hello, welcome to fishlore

In my experience flashing, rubbing, twitching is almost always a sign of parasites. Pretty much ALL fish have flukes to some extent. Their immune systems hold them at bay but if anything weakens them then like ICH the parasites will win out.

I would see if you can find PrazI Pro in the UK, not sure there. PrazI Pro is nice because it is pre-mixed, very gentle, safe for shrimp etc, can be used as a preventative or a couple times a year to knock them back. Treats a variety of parasites including internal. If you can't find PrazI Pro, look for praziquantel the main ingredient in it. If you find it I would do a few weekly rounds.

Is PrazI Pro safe for scaleless fish (don't mean to hI jack thread just curious)

Is PrazI Pro safe for scaleless fish (don't mean to hI jack thread just curious)

What kind of fish are you referring to?Supposed to be safe for all aquatic life except saltwater flatworms.

kuhlI loaches specifically

How I read the literature is it will only adversely effect worms and other parasites.

If a fish is heavily infested with flukes (like I've had fancy goldfish in the past who were), they will bottom sit and not feel well as the flukes exit their skin and leave little sores. But I've never had any issues with any of my fish. I don't have loaches.

ok thanks I will have a look also can I ask do you have experience in raising cory fry?

There can be lots of reasons for fish flashing.The first one and most common is (something in) the water. Did you recently change / renew filtermedia ?? Your fish look in very great health so I don't expect there to be some internal parasites. I wouldn't add meds if you're not exactly knowing what is causing this. Keep an eye on waterparameters !!!

What do you want to onow about raising Coryfry ?

yeh I had to do a 75% water change I was told that nitrate was a bit high I will test the water myself and well my baby corys have hatched and are free swimming but I worried about feeding them as I couldn't find any where that has baby brime shrimp I have jbl fry flakes which has 3 stages of food a lot of people told me to much water can drown them , how often and how much water do I change, how many times a day do I feed them I don't want to over feed them

Keep an eye on ammonia and nitrites !!! Before the waterchange they didn't flash??

Overfeeding isn't an issue, but waterpollution by leftovers is. I myself feed three times a day. First time only microworms and after that a variation of microworms, soaked / crussed pellets and a kind of protein breeding powder. Daily waterchanges cause of the pollution.

okay so do a daily water change? I'm having trouble finding any microworms or baby brime shrimp none of my local aquatic centre seem to have them at the moment I'm removing left over food well as much as I can with a syringe which takes me for ever lol I originally thought I only had 10 fry but in the fry tank there's a little space under the built in filter so when they became free swimming loads more turnt up. is it ok to use other tank water then treated tap water I have another tank which I take water from?

ok the only reason I was so against it being ick as its been a week and no noticeable white spots.can they take this long to appear?to me it doesn't seem like ich I will post a short video so maybe you could see

ok so there not flashing at the moment but maybe you guys can see something I don't?

Yes as I said before in my experience they begin flashing and twitching maybe a week to a week and a half before you notice the white spots...Try Seachem Paraguard it is also safe for scaleless fish... I have khulI loaches and every single one survived treatment.. Hope this helps

Are they rubbing at all? Against leaves? or bumping their stomachs on the ground or anything like they are a bit itchy. If so I would still recommend praziquantel, it is not an antibiotic, it is a de-wormer and recommended anytime you add new fish to your tank as it is gentle. I would keep my eyes on those things.There are many parasites, not just internal, flukes are external. If you continue to see symptoms that is not helped by lowering your nitrates, I would treat.

Daily water changes should not be needed on a cycled tank but a few larger ones to get your nitrates down under 20ppm would be helpful.

I have cories but no cory fry for Tyguy760 question. That link is good though.

ok great I used aquacare anti-fungus & white spot on my peppered corys as they had ich from a previous tank they were in them and black widow tetras were the only survivor's after a 14 day treatment I'm worried about using it with the fish I have in my tank?
is praziquantel safe with live plants to?

ok great I used aquacare anti-fungus & white spot on my peppered corys as they had ich from a previous tank they were in them and black widow tetras were the only survivor's after a 14 day treatment I'm worried about using it with the fish I have in my tank?
is praziquantel safe with live plants to?

Did you read the link I posted above? Its worth looking at by HikarI the makers of PrazI Pro.

I have used it more times than I can count over the last 4 years. I have never once had a fish death from it. I usually use it for 2 weekly rounds minimum. It is only active in the water for four days. I use it every time I introduce new fish. Safe for plants, I have a planted tank.

The fish I have used it on to date are: goldfish in the past and in my current tank I have: peppered and sterbaI cories, ghost shrimp, nerite snails, a blue Ram, a honey gourami, platies, guppies and mollies. My livebearer fry have never negatively been impacted by it.

Mostly I have used it when I see itching of new fish and internal parasites recognized by very long thick white poo. It cures both.I know lots of people here trust it, you could always start a new thread about peoples experiences with it to get opinions as I am only one personFYI The ingredients in the product you listed are :Anti-Fungus & White Spot Contents:

Malachite Green 140mg/100ml

Formaldehyde 800mg/100mlMy understanding is that malachite green is not safe for scaleless fish and should be used at half dose for tetras

Toxicity. Malachite green is quite toxic at the inflated levels recommended by its distributors, especially to fry and to adult tetras, loaches and catfish. Treated fish clear the drug rather slowly; its metabolites remain in their livers. showed that activated carbon had insignificant effect on formalin remaining in water. Together those factors can make a second dosing more toxic to the fish than the first one. Instead, water changes are needed to reduce the formalin levels. Formalin is also quite toxic to you. So scrub your fingers before you put them in your mouth. This quote came from the Skeptical Aquarist.

As said I really have my doubts why using any meds if there are no visible signs of any disease on the fish.

As said I really have my doubts why using any meds if there are no visible signs of any disease on the fish.


Sometimes the only sign of parasites are visual in the way of rubbing and flashing. Not speaking of disease as much as unwanted guests. Untreated skin or gill flukes or stomach parasites will cause death eventually. There is not a reason to wait until they are very sick to treat as the treatment I'm referring to is mild but very helpful and is also recommended as a preventative.

Sometimes the only sign of parasites are visual in the way of rubbing and flashing. Not speaking of disease as much as unwanted guests. Untreated skin or gill flukes or stomach parasites will cause death eventually. There is not a reason to wait until they are very sick to treat as the treatment I'm referring to is mild but very helpful.


We clearly have a different point of view on this Cindy. I didn't tell to wait till they are very sick btw !!

Ok yes, agree to disagreeI look at this like using flea prevention on a cat or dog, that's all. Everything I have read about flukes has led me to this conclusion.

I would agree totally with you in this regard on the use of antibiotics and not using until obvious signs of sickness manifest themselves.

yeh I will defo get hold of some if I can because I see you mentioned white stringy poo which I've seen in a couple of my fish

yeh that's why I haven't used any treatment yet because like you said I don't see obvious signs of illness there eating well there colours are bright its the flashing that's the only noticeable thing right now the only thing I hve done was raise temperature (info given to me by aqautics centre) they said this wil kill any parasite on the fish or tank but I didn't raise to 80f like they had told me I raised it to 77.4f 80 seems to high to me

Stringy poo indeed could be a sign !!!

Raising the temp to 77,4F doesn't have much use to kill any parasite.

ok so bad news one of my angelfish died this morning when I saw angelfish last night it had a pink cottony spot on its heads it looked like it was gasping for air it was just being pushed by water flow around top of tank now I'm really concerned for other fish

Have you said what size tank you have? How many fish? I read back through your initial post.
10% weekly water changes is not enough and would explain why your nitrates are so high. Also if you changed our 75% water with really high nitrates this could also explain the twitching and stress you saw your fish under. Even though high nitrates are bad for them, drastic changes in water levels can stress them too. With super high nitrates, better to do numerous smaller water changes like 30% twice a day so they have time to acclimate to the water. If you were doing larger changes weekly then the 75% would've been ok. Hope that makes sense.If this was me and my fish I'd treat especially since once has now died and you saw a pink fuzz on it. You are describing more than signs of parasites with your dead fish. I have used Seachem products seldomly as I rarely have fish disease in my tank, but have been very happy with them. They have not hurt anyone or the plants.

Look into Seachem Kanaplex which treats fungal and bacterial diseases. The main ingredient is Kanamyacin. They also have MetroPlex which treats protozoan parasites and anaerobic bacterial diseases. Main ingredient is Metronidazole. Neither of these has effected my nitrifying bacteria population.

I know you have been hesitant to treat but having fish deaths is a reason TO treat.

Good luck.