# Guppy Tank: Fish Staying at Surface



## LaneLester

I have 10 gal tank with ~15 guppy adults and a bunch of babies. Lately the fish have been mostly staying just under the surface, rather than swimming through the whole tank.

I thought this might be due to lack of oxygen. I have a very small filter that hangs on the side. It brings water in at its bottom and then spills the water out at the top. The top is about 1/4" above the surface of the tank's water, so there's a small waterfall effect.

I have a few live plants, but they are not growing much, unlike the situation in my 50 gal. tank. I suspect the light is not bright enough, and there's no outside illumination.

Do you have any thoughts about the fish congregating at the top?

Lane


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## 1077

LaneLester said:


> I have 10 gal tank with ~15 guppy adults and a bunch of babies. Lately the fish have been mostly staying just under the surface, rather than swimming through the whole tank.
> 
> I thought this might be due to lack of oxygen. I have a very small filter that hangs on the side. It brings water in at its bottom and then spills the water out at the top. The top is about 1/4" above the surface of the tank's water, so there's a small waterfall effect.
> 
> I have a few live plants, but they are not growing much, unlike the situation in my 50 gal. tank. I suspect the light is not bright enough, and there's no outside illumination.
> 
> Do you have any thoughts about the fish congregating at the top?
> 
> Lane


Does sound as though oxygen depravation could be the problem. Perhaps adding a bit larger filter would help. I would also suggest performing a 30 to 50 percent water change with fresh dechlorinated water close to same temp as the water in the aquarium.
Would perform the water change asap until you can get a larger filter.
You could also add an airstone but the surface turbulence would not benefit your struggling plants.
Should you decide on larger filter,,I would run both on the tank for a couple weeks then remove the smaller one. Hope this helps.


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## cbirk

You should also test your water as well, because it can also be a sign that there is some toxicity to your water, IE a high ammonia, nitrite, or nitrate content. I would do this first because it is easier and cheaper to test and fix than a low oxygen problem.


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## LaneLester

Thanks for the responses, guys. I'll carry out your suggestions in the order that seems best, as you noted.

Lane


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## Blaxicanlatino

is the tank cycled? i noticed that when my guppies do that, its usually because they became spooked by something (water change usually).


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## LaneLester

Blaxicanlatino said:


> is the tank cycled? i noticed that when my guppies do that, its usually because they became spooked by something (water change usually).


I did replace some of the water (20%) a while back, but I'm not sure when they started staying at the top. 

They don't seem as extreme about that as they were. I did clean the filter, and maybe that introduced enough extra oxygen to help.

An ammonia test was negative, but I still need to buy the nitrate and nitrite.

I have a spare submersible pump that I installed for a while, but in the small aquarium it seemed to create too much of a current... not that I know if that's bad or not.

Lane


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## redchigh

In my tank, I have a 10G tetra HOB filter. If the water level drops so that the water from the outflow 'falls' into the tank, my guppies swarm to the top.

If I raise the water level to where the outflow is, they go back to normal behavior. Perhaps they don't like the sound of trickling?

It works for me.... Try it.


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## LaneLester

Wow, that's interesting! I thought the waterfall effect would aid in oxygenation of the water. But I'll try your suggestion and see if there's a difference in behavior.

Lane


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## LaneLester

By George, I think you're right! About a half hour ago I filled the aquarium up to cover the filter outflow, and now the fish are pretty much evenly distributed at all depths.

Years ago my electronics genius brother-in-law learned about a hotel that had a fountain where water flowed down a long spillway. The fish in the pond at the bottom were always dying. His knowledge of frequencies, resonance, and such led him to suggest the structure of the fountain was producing lethal vibrations of some sort. The hotel modified the structure of the fountain, and the problem went away.

Lane


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## SeaHorse

Oh my goodness that is interesting! I have a wand with about 10 holes on the output of my canister filter and there is a constant trickling sound as the water returns to the tank. I wonder if it bothers them? !! Especially when you have suspicious deaths for no apparent reason. The LFS told me I was changing too much water, too often and being too nice... killing them with kindness. Like one a week was dying. But I was only changing water about 20% of 70 Gal every two weeks to 3 weeks. Hmmm... Things have settled but I hate losing them so I'm going to see about quieting the output. thanks for the info!!


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## cbirk

You can over oxygenate the water too. There was a case I studied in school once where engineers built a damn, and after completion hundreds of fish started dieing. Turns out they had build the damn too high, and it was causing an over oxygenation of the water. They build in "steps" for the water to drop down, so that it was not falling from such a long distance, and decreased the oxygen content. Problem solved.

Just some random info.


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## LaneLester

I'm glad you said what you did about suspicious deaths. I put a big bubbler "stone" in my 50 gal tank, and I've been having occasional deaths for no apparent reason. I'm going to pull the stone and see if that stops the dying.

Based on what cbirk said, maybe the hotel problem was too much oxygen or maybe cbirk's dam situation was actually sound and not oxygen. An auxiliary question would be, can you over-oxygenate water? No matter how much bubbling or whatever you do, there's going to be a limit to how much oxygen will stay in the water, based on the laws of chemistry.

Lane


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## cbirk

I have no idea about the waterfall at the hotel, however the damn was a case study, investigated by the Army corp of Engineers, and that was their findings. As far as the laws of chemistry, I assume you are referring to saturation laws, however I don't think that they apply to this scenario. Reason being saturation laws apply to how much oxygen will stay in the water if left undisturbed, where as you have a constant flow of in coming in this situation, it immediately rises to the top, by while it does it is sill within the water, meaning at that point I think it is possible for supersaturation.

But then again, I am a physics major, chemistry is probably my weakest subject :/


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