Why are my fish hiding under the in tank filter?

Question

I finally put some fish in my newly setup tank after 8 days. I checked the temp, have an in-tank filter and went to get some fish. I put them in the tank inside their bag to get them regulated to the tank temp, for about 1.5 hours as suggested. They were swimming around just fine for a bit, now they have taken to hiding under the filter and one has died. I have a Mickey Mouse, Red Sword Tail, Neon Tetra and a Mollie, the Mollie died. What happened here? I have/had all 4 fish in a 20 gallon aquarium. Do I need some sort of air pump/air supply? I can go get this easily about 5 minutes down the road, so please be serious. Thanks!

Thanks so much G, but I did learn about tank cycling. I also know how to use the internet, so I DID do my research. And I have a thermometer as well. So don't assume because I didn't type that I had a thermometer, that I didn't have one. i had someone come out and help me set up the tank properly, and make sure I had everything up and running. i took the fish back to the store, and got a few more tetra's instead.

Answer 1

The fish are probably all hiding because they were just moved to a new tank. They aren't that comfortable enough yet in their new surroundings to feel safe.

As long as you have a filter, you shouldn't need an airstone. Dissolved oxygen enters the water from movement on the water's surface, not from bubbles. Just be sure that your filter is close enough to the surface that it creates a "ripple" effect across the top of the water.

As far as why the molly died, it could have just been stress from the move. All the livebearers will do better for you if a little salt is added to their water (about 1 tablespoon per 5 gallons of non-iodized salt - this can be aquarium salt, or kosher, canning, rock, or table salt without iodine added which are the same, but cost less). The neon is more sensitive to salt, but should be okay with the amount given. The neon may not do well in a new tank - they are also more sensitive to water quality, and with the tank only running for 8 days, I doubt if it's fully cycled - this takes 3-6 weeks to get a stable environment that can handle the ammonia the fish produce. Tetras should also be kept in schools of 5+, so your little guy will be a bit nervous without members of his own type with which he can school. But I wouldn't advise adding more fish until you see how the tank handles the current bioload from the wastes the present fish produce. If you're test results are only showing nitrates after about a week, it would be okay to go ahead and add more fish.

Answer 2

I think the answer could be a couple of things.

First, an air supply (bubbler or tube is good) is a good option. It helps the water circulation and promotes the growth of algae (although to much algae is not a good thing)

As far as the fish hiding behind the filter, it could be a couple of things. I had two aquariums running at the same time and i found it to be a couple of reasons. First the water temp might not be up to what it should be. Often times your water heater is somewhere near the filter, and the fish will stay there because they in a sense keep warm and dont get caught up in the filters current by hiding behind it.

Also, if your filter uses carbon, make sure that you have rinsed the carbon filter to get out any access carbon, this can cause harm to the fish as well.

I had mollies for awhile, however they can be an odd fish to care for. Check with your aquarium to see what water temps your different fish prefer.

One other thing you might want to check, though it has nothing to do with the fish hiding behind the filter, is to check your waters ph/acidic values. Your fish store should have the testing supplies. If you are using city water sometimes it has a higher accidic value and most fish like about an equal balance. Just a thought...

hope this helps

Answer 3

I think the mollie dieing is just from the stressful move, And mollies prefer some aquarium salt in the water, (NOT table salt) And you got 1 neon tetra?, Neon tetra are schooling fish and need to be in groups of 6 or more, Get 5 more or the one you have just now will die of stress, As long as you have filter you do NOT need an air stone/pump, But the do help with aereation. Get ammonia,nitrite,nitrate test kits and keep and remember to cycle your tank.


~ GG

Answer 4

so many issues --

you need to learn more about cycling a tank. you don't need an air pump if you have adequate filtration.

it is summer. don't let fish get hot in your car or your home. when transporting them its best to buy them just before the store closes. a thermometer would be a better purchase than an air pump.

your neon need buddies. they shoal for protection and you will learn lots about "fish stress" if you do a little research.

mollies are very susceptible to lots of fresh water bacteria. it is usually recommended you keep them in brackish water and not fresh water.

Answer 5

the fish my be hiding for a couple of reasons..
1 of them could b from traumer caused from transfering them to one tank to another.
this might also explain their sudden death

try and arrange the tank to not b too cluttered as fish have been accustomed 2 b living in spacious arrangments. might sound funny but its true.
dont no to much bout the air pump but if its a reasonbale price then y not buy it

Answer 6

Yes you definitely need an air pump.