New fish in old cycled tank? - Tropical Fish Keeping - Aquarium fish care and resources
 
LinkBack Thread Tools
post #1 of 4 Old 07-28-2013, 12:26 PM Thread Starter
New Member
 
New fish in old cycled tank?

Twenty-gallon tank once housed 12 mollies, 5 serpae tetras over the past 4-6 years. The last inhabitant (except for two small spotted corys) died this morning, apparently of old age, as did all the others (no evidence of disease, deaths were spread out over long period of time). I'd like input regarding restocking the tank using the same water. I've read references to 'old tank syndrome' but rather unclear how it would affect new fish being added. (I do have an active 10-gal tank I could put the corys in if I need to change water, substrate, and recycle.) Thank you for any information.
Annalee is offline  
Sponsored Links
Advertisement
 
post #2 of 4 Old 07-28-2013, 01:09 PM
Member
 
jaysee's Avatar
 
Welcome to the forum

Old tank syndrome is where the water chemistry of the tank changes over time to be different than the source water, through lack of water changes. This change occurs gradually over time, and the fish adjust to it. However, new fish are shocked by it and die.

It's best to keep your tanks water chemistry as close to the source water as possible, meaning performing water changes with some degree of regularity will prevent old tank syndrome.

There's no need to restart the cycle. Just change the water and add some fish.

125 - BGK, chanchito cichlid, pictus cats, silver dollars, palmas bichir
125 - cichlids (severums, bolivian rams, chocolate), rainbows ( turquoise, red), loaches (angelicus, zebra, kuhli and horseface), plecos (BN, RL and clown), denison barbs, tiretrack eel, pearl gouramis, betta
90 - Congo tetras, african knife, upside down cats, spotted ctenopoma, kribensis, delhezzi bichir
2.5 - betta
jaysee is offline  
post #3 of 4 Old 07-28-2013, 02:28 PM Thread Starter
New Member
 
Do you mean change all the water? I do partial changes - approx. 1/5 to 1/4 - weekly, unless too 'busy" (lazy!), but never more than two weeks apart, and don't top off ttanks.

Reading your other posts - you are expert! - I'm thinking of restocking with all one speciies, like small tetras or danios. Would you recommend introducing all 15 or 20 into tank at the same time and from same source, or spreading it out a bit?

Thanks very much for your advice.
Annalee is offline  
post #4 of 4 Old 07-28-2013, 03:01 PM
Member
 
jaysee's Avatar
 
If you did regular water changes then old tank syndrome shouldn't be a problem. It would still be a good idea to do a large water change before restocking. Periodically it would be a good idea, after you have fish too. Small water changes just don't clear out the water like the big ones do.

Ask me something about plants and you won't think I'm much of an expert I know what I know and I know what I don't know, and I don't often speak about things about which I do not know.

Because your tank is/was lightly stocked, I would only add a few fish at a time. You can add more fish at once to a heavier stocked tank, but adding too many fish to a lightly stocked tank will cause a mini cycle. Not that that's the end of the world or anything, but why not avoid it if you can?


Sent from Petguide.com App

125 - BGK, chanchito cichlid, pictus cats, silver dollars, palmas bichir
125 - cichlids (severums, bolivian rams, chocolate), rainbows ( turquoise, red), loaches (angelicus, zebra, kuhli and horseface), plecos (BN, RL and clown), denison barbs, tiretrack eel, pearl gouramis, betta
90 - Congo tetras, african knife, upside down cats, spotted ctenopoma, kribensis, delhezzi bichir
2.5 - betta

Last edited by jaysee; 07-28-2013 at 03:03 PM.
jaysee is offline  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Tank Almost Cycled. Need Fish Ideas KrisPriewe Beginner Freshwater Aquarium 13 08-28-2012 09:48 PM
So my tank is cycled...fish question zeus50 Beginner Freshwater Aquarium 5 08-07-2007 06:42 PM

Posting Rules  
You may not post new threads
You may not 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