• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

Relationship between fish stocking levels and plant development with CO2

Joined
30 May 2015
Messages
26
There are a lot of variables in using pressurised CO2 and getting good plant growth development but one factor I rarely hear mentioned is fish stocking levels in a tank. Does it play any role in the use of CO2 and plant development? Does the person with the beautifully aquascaped tank and just a handful of neon tetras swimming around to make the plants look nice achieve their results because low stocking levels contributed to the overall setup? Do some people who achieve spectacular plant growth just not have any fish at all and this is why they get such good results. I'm sure I'm probably barking up the wrong tree but I'm desperate to identify why after a month of CO2 injection there seems to be a missing variable that is not promoting any form of plant growth in my tank. So, do fish stocking levels play a role at all and if they do what would that be?

I should mention my tank is of course both well stocked and heavily planted.
 
There are a lot of variables in using pressurised CO2 and getting good plant growth development but one factor I rarely hear mentioned is fish stocking levels in a tank. Does it play any role in the use of CO2 and plant development? Does the person with the beautifully aquascaped tank and just a handful of neon tetras swimming around to make the plants look nice achieve their results because low stocking levels contributed to the overall setup? Do some people who achieve spectacular plant growth just not have any fish at all and this is why they get such good results. I'm sure I'm probably barking up the wrong tree but I'm desperate to identify why after a month of CO2 injection there seems to be a missing variable that is not promoting any form of plant growth in my tank. So, do fish stocking levels play a role at all and if they do what would that be?

If anything high stocking will make your plants grow better. But it can also contribute to algae if light is high. Some reasons why high techs have few fish are:

CHeaper if they get gassed with co2 which is not unfrequent.
Buildup of organics/waste. See, in a high tech plants are already producing loads of waste so you if you add lots of fish on top of that then organics build up easier and you end up with algae.
Aesthetics. The main attraction is normally plants in these tanks and a school of fish looks nice.
O2 at night. It can get low if you dont aerate the tank well.

You can have a beautiful highly stocked high tech tank but maybe youll have to do more maintanance i.e water changes. You also need to dose enough nutrients for the plants E.I is a good starting point.
 
Thanks Jose

So high stocking could in theory lead to better plant growth. Well, I've got the high stocking levels but awaiting the plant growth. I hope I'm dosing enough nutrients because I am using EI at the moment and have been for the past month. This is what is confusing for me - I'm trying to tick every possible box - good flow, CO2, nutrients etc but it's not having any effect apart from causing plants to lose leaves and to lose some fish. This is why I'm trying to look for some other variable that people don't discuss so much eg fish stocking levels etc.
 
So high stocking could in theory lead to better plant growth. Well, I've got the high stocking levels but awaiting the plant growth. I hope I'm dosing enough nutrients because I am using EI at the moment and have been for the past month. This is what is confusing for me - I'm trying to tick every possible box - good flow, CO2, nutrients etc but it's not having any effect apart from causing plants to lose leaves and to lose some fish. This is why I'm trying to look for some other variable that people don't discuss so much eg fish stocking levels etc.

Fish stocking if doing EI wont do you any great benefit most probably. Look somewhere else. Good places to look are:

1) CO2, look for new ways to measure it i.e pH pen.
2) Are you dosing everything really including magnessium?
3) Dont fret over nutrient levels. Sometimes there can be precipitations due to hard water, some substrates etc. So if needed dose 2x EI.
 
Last edited:
I've got the pen and I get a PH drop from 7.1/2 to 6.6/5 over the course of the day. I know that a one unit drop is desirable but the problem with this is that with my current PH drop level some of my fish are gasping around lights off time and I presume that if I increase CO2 injection from 7.1 to 6.1 I'm going to be killing fish for the sake of some nice looking plants. I'm following an EI program which includes MACRO (potassium nitrate, potassium phosphate, magnesium sulphate) and MICRO (chelated trace). Is this wrong?
 
I'm following an EI program which includes MACRO (potassium nitrate, potassium phosphate, magnesium sulphate) and MICRO (chelated trace). Is this wrong?
Sounds good.

Do you see any abnormalities in the plants? Like holes in the leaves, stunted tips or smaller tips on the stems?
A photo of the whole thing could help.

I've got the pen and I get a PH drop from 7.1/2 to 6.6/5 over the course of the day. I know that a one unit drop is desirable but the problem with this is that with my current PH drop level some of my fish are gasping around lights off time and I presume that if I increase CO2 injection from 7.1 to 6.1 I'm going to be killing fish for the sake of some nice looking plants.
If fish are gasping then thats as far as you can go with co2 unless you up surface agitation which I dont really recomend ATM.

The ammount of co2 you need depends on a few factors. Main ones are type of plants and ammount of light. Choose easy plants. Red plants normally need a lot of co2 and also some carpet plants. If light is lower then co2 demmand will be as well. But unless you see the so called "co2 defficiencies" or algae I dont think there is a need to lower the light.
 
You would think that more fish would increase the level of carbon dioxide in the water because they breathe oxygen and excrete CO2 through their gills.
 
Back
Top