I don't understand why they're dying!

captmicha

Le tired.
Dec 6, 2006
2,052
0
36
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Maryland, USA
I have a 10 gallon with around 6 male guppies. I found one dead the other day and assumed that it got into a fight or something. Then the next day, I see another one lying on the bottom near death.

The tank is filtrated, has an air pump and the temp is room temperature. I did a recent water change.

The only thing that I did kind of out of the ordinary is that I put in fertilizers last weekend.

I have a single pot in the tank with plants and I put a small capsule of Osmocote Complete in the substrate in the pot. I haven't done this for like three months. I also dosed Seachem Flourish according to the directions. I did the same thing in all my other tanks too and there have been no deaths in the other tanks or sick fish.

I did a water check and the readings are concerning. pH is 8.0 in this tank while the water out of the tap is 6.8. Ammonia is .5 ppm and 0ppm nitrate and nitrite (not concerning).

Do you think it's the Osmocote and if it is, why isn't this happening in any of my other tanks??
 
pH of 8 and ammonia .5 my money is on lethal levels of ammonia. you should be reading 0ppm ammonia, 0ppm nitrItes and 10-20ppm nitrAtes in a cycled tank.

what is your substrate? are the rest of your tanks at 8.0 pH? what is your water pH after you let it off gas overnight? what product do you use to treat your water before adding it to your tank?
 
immediately do a water change and use prime

i would plan on constant water testing and changes until the tank is cycled
 
.5 ammonia with no nitrate is definitely concerning. Your tank is pretty heavily stocked and one plant wont be taking care of the whole bioload.

Water changes and possibly move over some established media to get the bacteria going...
 
in my experience, i lost a whole bunch of fish to what I believed was the plant food flourish. since then, i've switched to low maintenance low requirement plants like crypts and anubias without dosing. haven't lose a fish ever since.
 
It's hard for me to believe that flourish would be killing fish at any recommended dosing level...

IIRC Osmocote does contain ammonium nitrate, which could theoretically register some ammonia on a test kit that test for total NH3...that being said your tank is still heavily stocked IMHO

What is the filtration?
 
Ammonia is .5 ppm and 0ppm nitrate and nitrite (not concerning).

This definitely needs clarification. It could be the ammonia but the "nitrite (not concerning)" part could be a reason too. Are you mixing nitrite and nitrate there (ie: nitrate levels is within safety levels and nitrite is 0ppm)? If you are truely reading .5ppm ammonia, some nitrite, and 0ppm nitrate then this is not a cycled tank.

I personally wouldn't call 6 male guppies overstocked.
 
I also think that the stocking is basically fine, 6 male guppies are about 12" worth of bioload...considering the 1" per gallon rule was created for slender fish like these. Now, aggression and compatibility is another matter. But 6 male guppies are not creating a lot of waste.

The high pH is making the ammonia more toxic, but where is that high pH coming from? I don't know anything about fertilizing with Osmocote, so can't comment on that, but Flourish has never shown itself to be harmful in any of my reading or experience, and if you followed the dosing directions you ought to be fine. We are talking about a small amount of dilute fertilizer here.

I too, wonder what the filtration is...has it recently been overcleaned or anything?
 
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