Fish near bottom of tank - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old 11-08-2012, 03:57 PM Thread Starter
Algae Grower
jen0910's Avatar
PTrader: (0/0%)
Join Date: Jan 2008
Location: Edinboro, PA
Posts: 67
Fish near bottom of tank

I have a well-established, planted 29 gallon community tank with primarily tetras (cardinal, red-eye, pristella), a single ghost cat, a single zebra danio, and 2 amano shrimp. This tank has been running for 7 years and all of the fish (and shrimp) in the tank have been in there for between 6 and 7 years. The fish are all healthy and I have never had any disease in the tank.

The issue is that over time, all the fish have gradually moved downward in the water column. At this point, all the fish spend all their time in about the bottom 3" of tank. They swim around and are generally as active as ever but they never move upward into the water column. I'm aware that tetras are middle/bottom dwellers for the most part but even they spent many years in the middle of the tank. Danios are known for being top dwellers and yet mine is down with all the other fish, in the bottom 3".

Any ideas why this is happening? How can I encourage the fish to use more of the available space? Why are they staying low? There is a good variety of aquatic plants available to them at all water levels. I have a single, 65W compact flourescent but it's not a brightness issue - I had extensive duckweed at one time and enough long val to completely cover the surface and it made no difference. I have a Rena canister filter with a spray bar aimed to flow across the surface about an inch down. There is not very much turbulence at any water level and I did throttle back flow for a few days last week but did not notice a difference in the fishes habits.

Thanks in advance for any thoughts or insight.
jen0910 is offline  
Sponsored Links
post #2 of 4 (permalink) Old 11-08-2012, 05:28 PM
Planted Tank Obsessed's Avatar
PTrader: (14/100%)
Join Date: Sep 2011
Location: Beaverton Oregon
Posts: 498
they could be stressed or sick. fish usually hang at the bottom when there is a problem. is offline  
post #3 of 4 (permalink) Old 11-09-2012, 01:30 PM Thread Starter
Algae Grower
jen0910's Avatar
PTrader: (0/0%)
Join Date: Jan 2008
Location: Edinboro, PA
Posts: 67
Originally Posted by View Post
they could be stressed or sick. fish usually hang at the bottom when there is a problem.
Thank you for responding. The fish aren't stressed or sick and seem healthy, they come to feed when I put food in the tank and generally swim around the tank all day (albeit in the bottom area).

I am just wondering whether the metabolism of fish slows down over time which may make them more comfortable lower in the water column - many of these fish are twice the "lifespan" I have seen quoted in fish literature.
jen0910 is offline  
post #4 of 4 (permalink) Old 11-09-2012, 03:58 PM
Planted Tank Guru
PTrader: (0/0%)
Join Date: Jan 2010
Location: Contra Costa CA
Posts: 11,721
Danios are social fish. Since you have only one he is probably hanging out with the other fish, which generally are lower tank fish.

I'll bet if you get some more (about half a dozen) they will stay in the upper areas.

Other reasons for fish to stay lower:
If there are no plants that are tall enough to provide some protection from predators (birds, cats) the fish will tend to stay lower. They do not know that there are no predators in an aquarium.
If you do not already have something tall, add some plants that either grow tall, or float.

If you are feeding a sinking food the fish know were to wait for food. They are being rewarded for staying low. Buy some food that floats for a long time. There are fine pellets that float like this.
Diana is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome