What Could Have Happened ?

[andyg81]

my 3 ft 180litre has been up and running really well for about 9 weeks now. fully cycled, weekly 20-30% water changes and the stats have been perfect.
Nothing new added, no deaths, nothing removed from the tank, however on saturday a we were having a party at the house and a friend said that a couple of fish looked like they were acting strange.
Sat watching my tank for 10 minutes (which in fairness I hadnt done for a while as we have been so busy) and a couple looked like they had clamped fins 1 x platy and 1 x cory. checked my water stats

ammonia 0.5
nitrite - 0
nitrates - 20

now ive not had an ammonia reading higher than 0 for about 3 weeks.

3 weeks ago I did clean my fluval filter - but in used tank water and did daily water checks for the first week - all were fine.

now all of a sudden I get ammonia. I couldnt do a water change Saturday as I had no de-clorinator left so I did it yesterday (at least 50% change) stats went down to 0. and I will check again tonight as the fish in question still seem to be clamped, I have a hospital tank if I need to get them out but the airpump filter isnt cycled as I took it out my fluval to use a few weeks back when I had a sick platy and it hasnt gone back in yet - because im lazy and was going to leave it till my next scheduled maintenance on my filter which should be in 2 weeks time (6 weeks after last clean)

 

[Alm0stAwesome]

Is there any chance of there being a little hidden corner somewhere where fish poo and old plant matter etc may be accumulating and releasing ammonia? Maybe hidden behind an ornament or something where the flow of water might be reduced?

Do you have live plants? Are there dying leaves on them that may be releasing ammonia?

Last one lol, do you have snails, as one may have died and be rotting somewhere.

Those are my best guesses so far!

 

[ZoddyZod]

what's the full stocking on this tank?

I'll throw a theory that after you cleaned your tank filter and got zero readings for a week, there were not enough fish in there to produce enough waste to get to a noticebale reading of ammonia in that time frame, but after the week it slowly increased up to the 0.5 reading over 3 weeks.

However, if you've got a well stocked tank, my theory goes out of the window.

 

[andyg81]

stocking is as follows

1 x siamese fighter, 2 x corydoras, 2 x cherry barbs, 2 x harlequin tetra, 2 x lemon tetra, 5 x guppys, 5 x black widow tetra, 3 x rummy nose tetra, 1 x bristlenose pleco, 2 x electric blue ram, 2 x plattys, 4 x neon tetra.

so should be plenty, there is one corner of the tank (furthest away from the filter pipe) that does sometimes get a build up of waste but I focus on this area first when cleaning to make sure its all gone, the last water change was last wednesday (23rd) generally I do a water change every 7 days.

there are 3 live plants in the tank, one of which was going brown when I did the water change last week so I took all the dead leaves off it.

as for snails - not that I know of, as soon as I see one it gets taken out the tank, I found a couple when doing my last water change so again took them out.

I think im going to totally take the live plants out and replace them with new ones tonight and do a large water change and possibly a filter clean as well.

 

[ZoddyZod]

you only cleaned the filter 3 weeks ago, there should be no need to do that again and you will be removing some of your bacteria colony in the process.

sounds like it could be the decaying plants that are the culprit, but since you only have three in there I would've thought the filter would catch up in time for you to not have a spike.

 

[andyg81]

yeah i didnt really want to clean the filter again so quickly so might just remove plants and do a water change, add new plants and ferts and see what happens

 

[andyg81]

well i took all the plants out the tank and replaced with 3 new ones, 75% water change added stress zyme - normally use fluid filter medium when i do a water change but couldnt get any, obviously used de-clorinator as well. gave the tank a right good going over, everything out apart from gravel. - found 4 snails - GONE lol

fingers crossed readings drop again

 

[andyg81]

checked water this morning

Ammonia 0
Nitrites 0
Nitrates 30-40

will check again after work

I noticed that I have 4 fish with nipped fins as well ! seems one of my guppys has taken a likeing to fins !!! if he carrys on he will be removed, so far hes had a top fin from a corydorus, 2 guppy tails and a platty tail - I am not impressed !

 

[tomtomtom1230]

If it was decaying plant matter, all you would've had to do is prune what plants you have in the tank and remove any dead leaves floating in your tank, on the substrate or in the filter

 

[andyg81]

most of the leaves were decaying , in fairness they looked terrible so i got rid of them, I was only using under gravel fertilizer tablet type things and when I moved my plants round / hoovered a few week back the ferts were gone but I didnt add any more as the guy in the shop said that it would last 6 month - going to get some liquid ferts at the weekend when I try to find some more amazon swords as my plec used to love hiding under the leaves of the 2 I had.