Slow and steady death toll

[twubs]

I have recently become victim to a slow and stead death rate in the tank. No apparent reasoning each fish behavior has changed some prior to passing.
History
· 15 Gallon long with 20Watts of 6500k lighting.
· Tank completed cycling 12/20/10
· Running a Top Fin 20 HOB filter.
· Live plants include 1 spruce of Hornwort, a shoot of wisteria, 1 sord, 2 Anubis 3 Crypto and a java fern that is showing several plantlets that I will replant shortly.
· Plants are hosted on drift wood and gravel substrate.
Stocked with 2 Zebra Danios, 4 Mickey Platys, , 1 Dwarf Gaurami, 2 False Juli Cory Cats and 2 Ghost Shrimp. A breeder net is in the tank as a home to 10 Platy fry.
Liquid water tests showed that the tank has not entered a mini cycle and that things should be good.
· PH7.4
· AM 0 – 0.25
· Nitrate - 0
· Nitrite - 10
· Water temp 76
Over the last two weeks I have lost several fish. Time line of events:
· Oto – looked to have a large swollen belly
· Danio – nothing odd. Was very large and the leader of the shoal.
· I added fert tabs for the plants at this point
· Added Hornwort and Wisteria
· Rosario – was eating fine and then left his territory after adding the Wisteria and then two days later he passed
· 30% Partial water change. – AM back to 0.
· Danio – Seemed not to be eating great since the loss of the first Danio.
· Loss of a couple platy fry(~1/2 inch) in the breeders net along the way. 7 remain
I realize that some of the numbers of recommend fish numbers are not ideal. I would like to rehome some of the fish if and when I can determine the tank is health and restock with a different variations. I would like to rehome the remaining danios and the female platy. I will keep one of the fry and donate the rest to the LFS.
Was looking to get 5 or 6 white clouds.
So is there anything I am missing here?

 

[Tim Wheatley]

Small tanks have a harder time coping with change. A spike in a small tank is HUGE, while a spike from something dying or decaying in a big tank is hardly noticed by anyone except those who decide to eat it before you take it out.

I think you probably just had too much stock in there. When you fed the food probably rotted and when the animals pooped the ammonia got to a point where it was too much for the fish. In a small tank it's a really big problem to overstock like I think you were.

I think you just got caught out by spikes in ammonia due to the bioload of the fish you have.

How often so you change your water? I change 50% on every tank, every week. I'd also consider upgrading your filter. I use a 70 gallon rated filter on my 20 gallon long because once it gets full of debris it slows greatly. Your filter is probably rated for 20 gallons with NO MEDIA (as that's how they rate them).

 

[twubs]

Would putting a much larger filter on the tank create to much of a water stream? I purchased a 45 and then the advice of a trusted fish store employee. He has done well by me in most other advice said the output might be a little to much and that turning it down defeats the added value.

My water change is done every sunday and is gallons.

 

[Tim Wheatley]

You didn't say how many gallons you change, but if you are overstocked (which you were) you need to obviously be changing more than it's likely you were.

Too much what? Flow? Filtration? I've never, ever seen or heard of a healthy fish being sucked into a filter and some fish (particularly Danios) LOVE fast flowing water. I once poured danios into a tank from a bucket and the danio swam up the stream coming out of the bucket. As far as the flow is concerned, my 70 in the 20 has no affect on the swimming or orientation of the fish whatsoever. As far as filtration, it simply isn't possible to have too much filtration. When your 20 gets slower you may actually be underfiltering by a long way.

 

[twubs]

Thanks Tim. I meant to say that I do a 5 gallon change. Going to price out some new filters now and see what I can do.

 

[Tim Wheatley]

Sounds good, good luck.

If you can, especially if you are concerned about flow affecting the look of the tank, try to find one with a lip so that the water ends up coming out horizontally. If your water level reaches the output you shouldn't get so much disturbance.

 

[BigJim]

I'm not seeing anything obvious in your posts that would explain the fish deaths. An oto with a fat belly is usually a well-fed oto. They are sensitive to water parameters though. Danios are much tougher fish, so that worries me a bit.

I prefer to put large filters on my tanks. A bigger filter that is adjusted down still has the potential for more water flow. Larger filters usually hold more media so even if the filter flow is choked, you're still putting your water through more media. If you're seeing any ammonia, you're either overstocked or underfiltered.

Is there a chance you contaminated your tank? Did you bleach dip the plants? It's the only thing I can think of.

 

[twubs]

Will run water parameters again tonight and see what I come back with. If there is any sign of ammonia I will do another water change this evening.

No bleach dip for the plants however the hornswort was a lart bunch with some brown sections that may be adding some additional load to the tank if it is slowly decaying. I am hoping that it will come back now that is it in a tank and not being shipped all over.

Will let you know test results tonight. Thanks,
Rick

 

[Tim Wheatley]

At least you know now there's some sort of problem. It's sad that the fish had to die, but this is why they took Canaries down mines. Those fish which passed may have saved the rest.

 

[twubs]

The kids haven't noticed some of these guys missing yet but will need to have a talk with them if the gaurimi or the cory's were to go missing.

 

[twubs]

Test ammonia again tonight and there might be a slight trace. Did a 30% water change and retest again tomorrow.

 

[twubs]

Seems things have leveled off. Think there might have been a small amonia spike due to the horn wort shedding quite a bit of it's leaves and jamming up the filter intake. Had to clean the filter out.

Everything is back to normal I hope. Will either add some blood fin tetras or white clouds when I can rehome the platy fry and the female platy.