Tropical Fish Keeping - Aquarium fish care and resources

Tropical Fish Keeping - Aquarium fish care and resources (
-   Beginner Freshwater Aquarium (
-   -   how many fish to add per week rule.. (

smit3183 10-25-2011 08:38 PM

how many fish to add per week rule..
I wanted to add some bloodfin tetras to my tank, but the "rule of thumb " is to add no more than 3-4 fish per week, since this is a schooling fish how should i handle this? 3 one week, then 3 the next or all 6?

zof 10-25-2011 11:18 PM

Its not so much a per fish rule as it should be a percentage rule, if you had a tank of 50 fish then it would would be pretty safe to add 10 fish at once. Where if you have a stocking of 3 then adding 3 more will most likely result in a mini cycle not so much an issue as long as you keep an eye on your water parameters and do appropriate water changes. Of course there are a lot of variables such as how messy the fish are you are adding etc, just off hand it should be safe to add around 20% or less of your stock level and avoid a mini cycle for the most part. But since mini cycles usually only last a week or two and usually aren't all that bad most people will add in about 40% of their stock.

Of course there are always reason you might need to add more, such as introducing territorial fish at the same time so one doesn't claim the whole tank. Just use your best judgment on how much your bio filter can handle at one time.

1077 10-26-2011 04:23 AM

I look at volume of water when adding fish.
In 50 gal tank ,one could add five or six small tetra's at one lick without possibly seeing ammonia or nitrite's creep up assuming the tank has healthy biological filter (cycled).
Adding six small tetra's to Ten gal tank, would be more of a worry for there is less volume of water to help dilute possible ammonia /nitrites.
In both cases..alway's good to monitor (test) after ten or twelve hours of placing fish and perhap's daily for a week or more to see that biological filter is keeping up with the waste produced.

Jbrofish8 10-26-2011 06:32 AM

Also, is this tank planted? cycled?

I safely added 8 tetra to my 29g all at once without issue. My tank is very heavily planted though. Having plants really makes it easy.

AbbeysDad 10-26-2011 08:13 AM

When you consider all of the variables, there really can't be a rule of thumb regarding adding new stock...

> New tank, recently cycled or established.
> Water chemistry.
> Size of the tank.
> Condition and maintenance of tank and substrate.
> Plants.
> (Bio) Filtration.
> Existing bio-load - proposed new bio-load.
> Feeding amounts and methods.

Any one of the above (and others I haven't thought of here) leaning on a negative side totally changes the equation. We must use our best judgement and better to err on the conservative side than to throw money away and torture poor defenseless fish.

If we have an established eco-system and make changes in stock, filtration and/or maintenance, we need to perform water tests and/or observe stock to better ensure against negative reactions. If/when there are negative reactions to change(s), we need to be prepared to perform corrective action(s) quickly as needed.

smit3183 10-26-2011 09:09 AM

55 gallon tank that has been cycled for 3 weeks, current fish, 5 zebra danios, 2 platys, did have 2 giant danios that were removed from tank. 8.3-8.4 really limits my selection of fish. No live plants . Running 2 fluval C4 on low flow
Posted via Mobile Device

Only One Haze 10-26-2011 09:36 AM

Its been cycling for 3 weeks or it finished the cycle 3 weeks ago? If the cycle has completed I would think adding all 6 Tetras together would be okay in a tank that size.

smit3183 10-26-2011 10:33 AM

Finished the cycle
Posted via Mobile Device

Byron 10-26-2011 12:22 PM

I agree with all that others have posted. The entire system has to be considered.

In your case, add the 6 fish. Live plants would make this a non-issue. But even without, the time taken for bacteria to respond (= multiply) to an increase of ammonia and then nitrite in that large a water volume would be around 20 hours total, given your water parameters.

All times are GMT -5. The time now is 01:33 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

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