Sick Platies!

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.


Aquarium Advice Newbie
Mar 18, 2016
Hi everyone. I have sick fish that I am very concerned about and need advice! I have a 46 gallon glass aquarium with: two common goldfish, four platies, and one male betta

I am convinced that all of PetSmart's fish are diseased. . I recently purchased 4 Glofish Tetras, the betta mentioned above, and 1 dalmation Molly from there and put them in the tank with my platies and goldfish. Soon after my fish started acting funny. I did a 60% water change, but this time I used the outside hose pipe (we have well water) and let it slowly run into my tank (I did add water conditioner). This made the temperature go from 75 deg F to about 65.. but it was over 35 minutes at least. Soon after that water change my female platy worsened (starting staying on the bottom instead of randomly laying there and got skinnier). I took out the Glofish because they became a little aggressive (I now know that they prefer groups of 5+); the purple one (that looks pregnant to me) started chasing my betta and biting his tail! I moved them to their own 10 gallon and the nexy day I noticed white specks on their fins (assuming ick)--I treated it with large water changes and salt and they are perfectly fine now. I just had to move the Molly in with them, because he/she started being aggressive towards my other fish when eating. *Note that the molly seemed unhealthy to me after I purchased it-- it would randomly twirl on the bottom for a second or two. It only did that every once in a while each day the first week. Just before moving him today I've noticed him laying around the bottom, but he doesn't do that in the 10 gallon now.

Now, a few weeks later, it seems like all of my fish in my 46 gallon are infected with something or different things.

** do you think that the new glofish and/or molly infected my other fish? or do you think that some kind of parasite or something was introduced when I used the outdoor hose pipe to do a water change? Do you think it affected them because of the temperature drop as well? **

*My two adult platies (the other two were the female's fry that survived): both seem to be infested with a parasite or some infection. My female platy started by sitting at the bottom very often, like she was so stressed and weak. I assumed it was because she was the only adult female (when I bought her last year I didn't realize she was female) and she was tired from the male chasing her. But, as I said above, she started staying on the bottom a lot. And now she has a place missing from her tail and is very very skinny, instead of her usual plump self.She also now swims in more of a wobble style and uses her whole body to get around. Today the male platy has had clamped fins, one white spot on his left side where the tail fin starts, and sometimes struggles to stay in a horizontal position-- he starts being face down and tail up.
*My goldfish: are their usual selves, just looking for food constantly, but one has a few rips in his tail and sometimes they'll both hang around the bottom and will twitch and bolt around the tank a little.
*My betta: has rips or pieces gone from his tail, but I think he is otherwise normal.
*all of my fish are eating well.

These are the tank's water conditions: 70 ppm nitrate (seems like they won't stay below 30 no matter what I do, but today for some reason they're 70!), 0 nitrite, 75 ppm Hardness (GH), 6.8 ph and 40 ppm Alkalinity. Using the Fluval 70 HOB filter (lovvve this filter btw!) I am about to do a water change because of this spike in nitrate. I did ad a teaspoon of baking soda this morning for the first time because I have always had 0 alkalinity and 6.2 ph and after doing research I decided to add it. My tank has artificial plants only (but I would love any recommendation of FW plants).

:fish1: Sorry this was a long post! I just wanted to be as detailed as I could so anyone wanting to help has all the info they need to help me. Thanks so much ahead of time! I attached two photos and one video.


  • DSCN0993.jpg
    253 KB · Views: 69
  • DSCN0991.jpg
    251.7 KB · Views: 64
Looks like my video didn't upload. If I need to upload more pics let me know. Thanks
First off don't buy fish from petco or petsmart go to a local fish store. Your platies seems like it has internal parasites. Is her poo stringy? If so treat her with metronidazole. Goldfish are cold water fish and can't be kept with platies which are tropical fish. The male betta has to be in a tank of their own or they will their tank mates.
Khua, thanks for the reply. I was afraid I would be told it was a parasite. I definitely won't be buying fish from petco or petsmart anymore. Yes, I have noticed stringy poo, but mainly from the female that is very skinny that's in the picture above.

As far as the goldfish, I am aware that they are coldwater but I rescued them and do not have another place to put them..their previous owner kept them in a tiny betta fish container, so this is much better for them than that at least. I keep the water at 75 so it's a happy medium for everyone. I used to think that about the betta fish, but I know of several that keep them in a community tank and did research and from what I have read, they are fine with others as long as they don't have long flowing tails or very bright colors. He seems to get along well with everyone and is a sweetie from what I've seen.

The male betta has to be kept in a tank of its own or it will what their tank mates?
I usually do a 50% or 60% change every two weeks. It's only been about 9 days since my last water change, but because of the high nitrate levels I did an 85% water change last night. I tested again this morning and they hardly dropped! I don't understand what has them so high, do you?? If I did a water change every other day, my nitrates still won't go below 20-30 ppm.. I am guessing it's just our well water. But I cannot figure out why they went up to 70+ ppm, and are still at about 60 after a huge water change. Their tank is not full of food and poop, it is very clean and stays that way.
Any advice? I've never had this happen before.
Goldfish produce a lot of waste which leads to high ammonia. Your filter will turn ammonia into nitrite then to nitrate. I would test your well water to see if nitrates are high just from the start or maybe it's the goldfishes waste. If the platies have stringy poo it's a sign of internal parasites and will need to be treated with metronidazole.
I will definitely treat them with metroindazole. Any brand you recommend?
I have had these goldfish about a year and they actually seem to be so clean. My platies poop much more than they do I believe. I love that they are always filtering through the sand looking for food, it really plays a huge roll in that sand staying so clean. I haven't ever had a problem with nitrates with them before.

I tested my well water straight from the sink and the readings were 20 nitrate, 0 nitrite, 0 alk and 6 ph. So I guess my well water is just that way.
I would use seachems metronidazole and treat the food and water column as well. Follow the directions on the bottle. I don't remember if it tells you how to soak the food. I would get a small cup fill it halfway with tank water mix just a little of metro. I can't remember the exact amount, google it and I'm sure you will find the recipe for. Try doing weekly 30% water changes and see if that helps bring your nitrates down.
Top Bottom