High Phosphate in Aquarium

[Bertron]

Hello, recently I have had several fish die in my 25 litre tank, these include 2 bettas (females) 4 kuhli loaches, 4 corydoras. I have 10ppm levels of phosphates, having changed 25-30% of the water several times and added phosphate absorbing filter media i still have high levels (5ppm+) . My next course of action is to pull out all the plants and vacuum the tank. Does anyone else have any ideas on reducing the phosphate levels?

I have read mixed information as to whether phosphates are lethal to fish, could it be something else killing them off? I have not had this trouble before and have had the tank for 2 or 3 years?

I only have 3 kuhlies and a bristle nose plec left now

Any wise old owls out there with some advice please??

[Zev]

Have you tested the water that you are putting into the tank, sometimes it is high in phosphate before it even gets to your tank.

How often do you change the water?

[Caryl]

If the tank has been runnning that long and the problem with deaths is recent, I doubt it is phosphates (unless council has added something to the water supply). Our water is naturally high in phosphates too if I remember rightly and my fish are unaffected.

Did the fish all die within days of each other? 25L is not very big and you had 12 bottom dwellers in it, albeit small ones.

What is your usual routine maintenance (how often and how much water do you change regularly?) and have you tested the pH, ammonia, nitrite and/or nitrates? These would be more likely to cause deaths than phosphate levels I should think.

[Ira]

Phosphates at that level are not harmful to fish. They can be MUCH higher before they care. Other than it encouraging algae growth, in FW you can basically ignore it. I'd suggest testing your ammonia, nitrite and nitrate. THOSE are the ones you need to pay attention to. Especially in such a small tank.

[ryanjury]

I had phosphate issues and traced it back to the food I was feeding so maybe change foods and see if that helps? I had lime green water and phosphates off the chart and none of the fish were affected it just looked bad when you stuck the water in a bag to catch fish..

[Bertron]

Thanks for the suggestions everyone, I have bought some additional nitrogenous test kits and will have a go at those tomorrow morning.

I did buy a few new fish recently ( now all deceased) so maybe they brought something in with them, although I lost a couple of kuhlies before they arrived. If the water has acceptable levels of other contaminants, I will keep monitoring and lay off of buying anymore fish for a while.

I have already checked the water I was using to replace the old water, it was approx 0-1ppm Phosphate

Will keep you posted on my progress, thanks again for the advice

[Bertron]

Well the nitrates and nitrites were all low, and now after a jolly good vacuum and water change the phosphates finally are down. I even found another kuhli or two (have 5 now) Will monitor weekly and then get some new fish after a month of stable readings. Maybe my new fish brought in some disease with them...