Platy Flashing for Unknown Reason

I set up my 20 gallon planted tank 5 months ago, and cycled with both pre existing media and two platies. One of the platies made it through the cycling process and is still in the tank today. Around the two month mark, the cycle was complete and I started to notice my lone platy flashing against plants for unknown reasons. I began to worry about ich, or possibley an external parasite of some kind, but never saw any other symptoms. Eventually the flashing seemed to calm down, and I only ever saw her do it on rare occasion. I went ahead with stocking the tank, buying two more platies. They immediately began to flash not even 20 minutes after placing them into the tank. (I did go through a drip acclimation process). At this point the flashing began to drive me crazy as it would go through points of being often (1-3 times a minute) to hardly at all. One of the females I purchased gave birth and because of how heavily planted the tank is, I had over 14 fry survive. And once they got big enough to swim about the tank, they too could be seen flashing on the plants.
A few weeks ago it had gotten to the point where again I almost never saw them flash, so I purchased four corydoras catfish. They have never flashed before, and seem perfectly happy. The orginal fish I purchased (the one that helped me cylce the tank) now NEVER flashes, although the two newer ones still do. The only thing I can think of is my PH and water hardness being too low for the platies. As I know cories enjoy more acidic water.
I should also mention that all other behaviors have been normal for months. No sign of illness, no stress, no gasping, no clamped fins, and they eat readily everyday. Even all the babies are still alive and growing at a fast pace.
I use a digital PH meter, which I don't 100% trust. It's measurments are telling me my PH is 7.2-7.4 consistantly. The first few weeks I used test strips, which always told me I had very soft water. Tempurature is always 76°-82° F. I know that seems warm, but it is summertime here and the fish don't seem to mind.
Nitrite is consitantly 0
Nitrate is always less than 10ppm
Ammonia 0

Besides PH, I think it's also interesting to note the flashing started right around the same time I switched to Seachem Prime for my water conditioner. I've never heard of prime causing a problem before, but it could be the issue.

Any possible solutions would be great! I think with the next few water changes I'm going to swap off of prime to see if that helps. The only other solution I'm considering at the moment is placing the platies in another 20 gallon with a crushed coral substrate, which would cost a bit to get running and I hope to avoid.

Thanks!

 

welcome to fishlore! there are several reasons for flashing. But it looks like you've eliminated the possibility of it being ammonia. Though do you use test strips or the apI master test kit. I ask because the test strips are not consistently accurate where the liquid test kits are. I would consider switching

Another common reason for flashing is poor acclimation. Though I don't see this being a reason, the fact that your temperature varies so much could be causing issues. Are you saying it adjusts within 6 degrees each day? Or is this the year round range? And really low 80's isn't too bad as long as it's not permanently there.

The other potential cause would be gill/skin flukes. Do you notice if they have their gills clamped? Or irritated? Does their skin have what looks to be bruises or darker spots? The other obvious is ICH but if you haven't seen white spots in over 5 months then that is highly doubtful.

 

Hi, thanks for the reply! My temperature does fluxuate over the course of the day, ranging from 76 in the morning and evenings and peaking at 82 during the day. I'm not exactly sure how I could combat this however.
I use seachem liquid tests, but I only have Nitrate, Nitrite and Ammonia. I used test strips only for the first few weeks of the tank being set up.
I ruled out ich because there definitely isn't any white spots. I've considered the flukes, but every time I consider medicating the flashing seems to calm down. I really don't want to dump medicine in unless I have to.
The only other thing I use besides prime is API leaf zone for the plants. That is dosed once a week per instructions on the bottle.

 

To combat the temperature swing, you could up your heater to 77 or 78. I have a similar issue and during the summer months my water stays around 80 naturally. Though fortunately I have fish that do just fine at this temp so I set my heater to 80 so it's always there.

Do you have a hospital tank?

 

I do have an empty 10 gallon I could set up as one. Is there any medicine you reccomend? I went out and bought seachem paraguard a few months ago when I was considering medicating. Would this do the trick in the hospital tank?

 

I was just thinking maybe taking one of the fish that is flashing the most, and moving it to the hospital tank. Paraguard is a good one but I believe a better one for flukes is prazipro. It's a very gentle medication that will do a more thorough job than paraguard I believe. I've used it several times even on my kuhlI loaches with no ill effects. CindiL can give better advice than I on prazipro and advice on treatment. She's the one I got this advice from

 

Thank you so much for the advice, I have a few things to try now! Fingers crossed.

 

Hi, welcome to fishlore

I second getting PrazI Pro, it is very gentle and get be used as a preventative even with new fish. It is in liquid form, 1 capful per 20gallons. I would do a couple of doses a week apart with a water change in between. Make sure to remove carbon.

 

Would dosing in my main tank be alright without setting up a hospital? Or would it still be a good idea to separate the fish that are flashing? I ordered the PrazI Pro and it should be here in a few days.

 

I would treat your whole tank and not move the fish into a separate tank. Everyone will probably benefit from the treatment. Just FYI if they're heavily infested then after treatment you might see them slow down or sit at the bottom of the tank a bit because its uncomfortable as the flukes leave their skin. I just mentioned it so you don't think its the medicine itself which is very gentle.

 

Agreed. I suggested moving one and dosing so you can keep a close eye on one to see if the treatment was having an effect. Also in a smaller tank means less medicine. But if the majority of the tank is flashing then treat the whole tank