Why do all the fish come out after a water change?

[Flagpull]

After I do my weekly water change why do all of the fishies (even my mandarin who I hardly ever see) come to near the top of the water, the pink spot watchman goby even makes a trip up near the top...

Is it because some stuff gets stirred up and they want to see what's going on, or is it something else? I think my dottyback and clownfish get confused having visitors :)

[Mud Shrimp Moe]

They're probably a little shocked. Are you matching temperature carefully?

[KDodds]

No idea, but it seems rather odd. Do you change in the main tank? Or in the sump?

[Flagpull]

I have no sump (no room for a sump :( ) so yeah, in the main tank...match temperature as carefully as posible....and add the water slowly.

Things return to normal in a matter of minutes...

[KDodds]

Well, my guess then would be that they think they're getting fed, either because of normal feeding practices or because of the "influx" of "new water" that might bring tasty morsels along with it.

[HippieSmell]

If your new water isn't aerated, it might be because they are coming to the surface for more oxygen.

[KDodds]

Marine fish move DOWN for more O2, not up like FW fish. Reason being the lower temps the deeper they go, the more O2. ;)

[Entropy]

My guess is the feeding theory as well. My fish come up to the back corner anytime anything changes. Even when I add calcium. :rolleyes: The best part is when all my fish are out looking at the back corner. People ask me, what are they all looking at?

[Ehydo]

Originally posted by KDodds
Marine fish move DOWN for more O2, not up like FW fish. Reason being the lower temps the deeper they go, the more O2. ;)

That is not true. The lower they go the colder it gets. There is not more oxygen lower in the water but their bodies need less oxygen in colder waters. It is the same for most animals.

They will go to the surface for oxygen. Try aerating the water before you do a water change.

How big is your tank and how many fish do you have?

[KDodds]

No? Colder water doesn't hold more O2 than warmer water? What you suggest also contradicts everything seen in low O2 situations in tanks. Marine fish deprived of O2, move to the bottom of the tank, not the top.

[fishinchick]

Dont you dig hanging out in your house after going through and giving it a good through cleaning? ;)

So do they.

If you are mixing your water for 24 hours before using it you shouldnt have any problems. If you are mixing and using it before then you are probably shocking the fish and they are trying to find an escape perhaps. Bag Salt makes ammonia when newly mixed and will burn the gills out of the poor fishies heads.

[HippieSmell]

Originally posted by KDodds
No? Colder water doesn't hold more O2 than warmer water? What you suggest also contradicts everything seen in low O2 situations in tanks. Marine fish deprived of O2, move to the bottom of the tank, not the top.

Regardless, I would try aerating the water to see if anything changes.