Why Do The Fish Stay On One Side Of The Tank?

Discussion in 'Freshwater Beginners' started by JRS, Apr 20, 2017.

  1. JRSWell Known MemberMember

    I have had had some trouble over the last month with nitrates and illness, but I think that is almost behind me.
    Now that I am not putting out fires each day, I am realizing that the fish are always on one side of the tank and I am curious as to why. I know the glo-tetras are very fond of the fake bonsai. Now when the two healthy Black Neon tetras and the rasbora are very active they do swim around the whole tank. Otherwise they all tend to be on the left side.

    I have theories, but don't know.

    1 Is it because of all the stress they have endured they want to be together?
    2. Is it the heater being on the left? Should I have it centered.
    3. Do I have the water flowing, disturbing the water too much on any one area?
    There is a power head pointing up just to the right of the heater, a penguin 150 right of center and then an air stone in the right rear. They don't seem to have trouble navigating the water as I don't think there is any current.

    Now that the fish seem stable, I can start trying figure out these other details, working on stocking, etc.

    Attached Files:

  2. ZahcWell Known MemberMember

    I would say they are chasing heat, or it could be where the water flow is most comfortable.

  3. JRSWell Known MemberMember

    Maybe I should put a thermometer on the other side of the tank to see if it is different. Any recommendations on where the pieces are located?

  4. FashoogaFishlore VIPMember

    This is way left field but somebody probably farted or vomited at the other side.

  5. KimberlyGFishlore VIPMember

    Do an experiment to see what they prefer. First change the decor. Swap the bonsai to the right side in front of the filter intake. Put the gold plant in front of the heater. See if they follow the bonsai or stick to the heat.
  6. PunkinWell Known MemberMember

    Mine tend to hang out more often on the left. For my tank, that is under the filter and opposite side of the heater. But I mostly think it's because that's where I feed the cories and they wait for food bits. Is there more coverage there?
  7. JRSWell Known MemberMember

    I just checked it is 2.5 degrees warmer on the heater side.

    That is a great idea. I think I will try that tomorrow. Thanks.

    Coverage as far as hiding places or coverage of water flow?

    From all the posts I see about cories, they seem to be little piglets! They are cute.

    Hiding places.

    I thought that was what you meant. Seems to me there are hiding place on both sides, but that corner tends to be darker if the lights are on in the room. I will have to sneak in when the lights are off in the room and see. Tricky fish.
    Last edited by a moderator: Apr 20, 2017
  8. PunkinWell Known MemberMember

    They may like it because it's darker. Come to think of it, my left corner is darker too.
  9. lyfeoffishinValued MemberMember

    Fish tend to stay close to cover. I know in my tank most cover is on the right side of the tank (working on that now) and that's where the fish stay unless the room is very still and they are comfortable. Although when lights go out and fish go to sleep they tend to sleep throughout the tank on both sides.
  10. JRSWell Known MemberMember

    Come to think of it, when I go in early and they are sleeping a couple do sleep on the other side down low.
  11. PunkinWell Known MemberMember

    Mine also seem to sleep all over the tank.
  12. JRSWell Known MemberMember

    Curious! Tomorrow when I have a little more energy, I think I will try and move the tree and see what happens. I think ultimately, I will move the heater to the center or when I upgrade them to the larger 29 gallon.
  13. Tiny_TanganyikansWell Known MemberMember

    There's so many reasons why, it could be the layout of the tank/decor, the way light bounces around, where they feel safe with something overhead etc etc

    The most common reasons is the flow, and temperature. Incidentally they're connected.

    You may have too much flow/not enough

    The way your flow is setup from the filter/powerhead/airpump etc

    You might not be circulating the water efficiently so they might be staying in the oxygen rich spot or the prefered temperature.

    The heater should be wherever there's the most flow (filter output)

    Filter input and output should be on opposite sides of the aquarium. This is hard to do with hobs/internal filters, but with a little superglue/silicone/pvc you can make your own spray bar to circulate rhe water better
  14. JRSWell Known MemberMember

    I would love to know how to go about this. I will have to investigate. Thank you.
  15. Tiny_TanganyikansWell Known MemberMember

    I have a couple HOBs and an internal filter that I fit with PVC. All I did was cut out a little piece in the side of the pipe just the right size to attach where the water comes out. I capped both ends of the pvc and drilled small holes on the furthest end so the water would go to the opposite side of the aquarium. I superglued it into place and added a little silicone for good measure. I also spray painted the pvc black so it didn't stick out like a sore thumb. You can also put a length of sponge or floss inside the pvc and get extra biological filtration

    Since the water is not contained and completely forced through the pvc a little might overflow but not much. It depends on the flow rate. Mine just have a little trickle I'd estimate that 90% comes out of the "spray bar".

    I originally did this to solve two problems.
    One to baffle the filter so it wasn't too much flow for a betta. Two because I prefer much longer aquariums opposed to taller, so I needed to make sure the water was well circulated.
    Last edited: Apr 20, 2017

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