Newbie looking for guidance on stocking levels

[TheHumm]

Hi, all! I am new to fish keeping. After a little over 6 weeks, my tanks--quarantine (QT) and "main" (MT) have both cycled without fish. I read some advice, however, that I should continue adding ammonia and doing water changes until the biofilters can neutralized 2 ppm of ammonia within 24 hours before adding fish. (Don't know if it really needs to be done, but it sounded like a laudable goal...) I'm making progress doing that, and expect that process to complete within the next two weeks.

My present concern is determining how many fish I should ultimately house in my MT, and how many fish I can safely add at one time as I am building up my stock. I have looked at a few different "stocking calculators", but each comes up with different recommendation. I have also heard that experienced fish keepers just have a "feel" for how many fish a tank can safely accommodate. I will be looking through the posts on this site for guidance but, in the meantime, I thought I would post the question and see if any kind, experienced fish keeper(s) here want to offer guidance.

Tank specifics:
QT is a 20g long with one Seachem Tidal 55 HOB filter, thin sand substrate and very light artificial decor (so I can observe the fish for signs of disease.) Because this tank is so sparsely decorated, it was cycling *much* more slowly than the larger MT, so I doubled the amount of biomatrix in the filter, and that sped up the cycling nicely.

MT is a 40g breeder with two Seachem Tidal 55 HOB filters, 2 inch sand substrate, driftwood, rocks, and quite a few (all) artificial plants. (Since I am new to the hobby, I wanted to concentrate on keeping the fish alive, rather than the plants. I'm really bad with house plants...)

Eventually I would like to have the MT stocked with a school of zebra danios, a school of harlequin rasboras, and a school of either emerald green or peppered cory cats. (Depending on which corys I can actually get. Dealers around here are reporting that they are having difficulty getting corys from their distributors right now.) Simple fish, I know, but what I find really fascinating about fish is their schooling behavior. And so, both for the fishes' comfort and my own enjoyment, I'd like schools that are as large as is safe.

I think I'm going to keep the cory school to 6 individuals. It's the sizing of the rasbora and danio schools that I'm not sure about. AqAdvisor says I could have a school of 12 rasboras and 10 danios and still be well under the stocking capacity of the MT. But that seems large by both the inch-per-gallon and inch-per-surface-area rules. I don't want to overstock/overcrowd the tank.

I also am a little confused about how many fish I can safely add at one time to either the QT or the MT as I build up my stock. Since these are schooling fish, everyone says they will experience less stress if they are in groups of their own kind--the larger the better. But everyone also says not to add too many new fish to a tank at one time, so you don't overwhelm the biofilter. 'Tis a puzzlement.

I'm sorry this post is so long, but I am trying to anticipate questions others might have. Thanks for reading!

 

[xxEMOxLIZZARDxx]

Hi, all! I am new to fish keeping. After a little over 6 weeks, my tanks--quarantine (QT) and "main" (MT) have both cycled without fish. I read some advice, however, that I should continue adding ammonia and doing water changes until the biofilters can neutralized 2 ppm of ammonia within 24 hours before adding fish. (Don't know if it really needs to be done, but it sounded like a laudable goal...) I'm making progress doing that, and expect that process to complete within the next two weeks.

I will leave this to someone more experienced.

My present concern is determining how many fish I should ultimately house in my MT, and how many fish I can safely add at one time as I am building up my stock. I have looked at a few different "stocking calculators", but each comes up with different recommendation. I have also heard that experienced fish keepers just have a "feel" for how many fish a tank can safely accommodate. I will be looking through the posts on this site for guidance but, in the meantime, I thought I would post the question and see if any kind, experienced fish keeper(s) here want to offer guidance.

What are your water parameters? Do you have hard or soft water. That dictates what fish you can keep. You can find this from your local water source website.

Tank specifics:
QT is a 20g long with one Seachem Tidal 55 HOB filter, thin sand substrate and very light artificial decor (so I can observe the fish for signs of disease.) Because this tank is so sparsely decorated, it was cycling *much* more slowly than the larger MT, so I doubled the amount of biomatrix in the filter, and that sped up the cycling nicely.

I think quarantine tanks are suppose to be void of items, but again, I'll leave this to a more experienced member.

MT is a 40g breeder with two Seachem Tidal 55 HOB filters, 2 inch sand substrate, driftwood, rocks, and quite a few (all) artificial plants. (Since I am new to the hobby, I wanted to concentrate on keeping the fish alive, rather than the plants. I'm really bad with house plants...)

Eventually I would like to have the MT stocked with a school of zebra danios, a school of harlequin rasboras, and a school of either emerald green or peppered cory cats. (Depending on which corys I can actually get. Dealers around here are reporting that they are having difficulty getting corys from their distributors right now.) Simple fish, I know, but what I find really fascinating about fish is their schooling behavior. And so, both for the fishes' comfort and my own enjoyment, I'd like schools that are as large as is safe.

I think I'm going to keep the cory school to 6 individuals. It's the sizing of the rasbora and danio schools that I'm not sure about. AqAdvisor says I could have a school of 12 rasboras and 10 danios and still be well under the stocking capacity of the MT. But that seems large by both the inch-per-gallon and inch-per-surface-area rules. I don't want to overstock/overcrowd the tank.

Cory cats need to be in at least a group of 10 or more. Same with the danios and rasboras. Although I think more along the lines of 15 fish per group would be even better.

I also am a little confused about how many fish I can safely add at one time to either the QT or the MT as I build up my stock. Since these are schooling fish, everyone says they will experience less stress if they are in groups of their own kind--the larger the better. But everyone also says not to add too many new fish to a tank at one time, so you don't overwhelm the biofilter. 'Tis a puzzlement.

I'm sorry this post is so long, but I am trying to anticipate questions others might have. Thanks for reading!

 

[10 Tanks]

Hello. Good question. I don't keep small tanks. The smallest I have is 45 gallons. But, if you're willing to change half the tank water every week, you can keep a few more fish than someone who changes the water less often. In one of my 55 gallon tanks, I have roughly 150 small fish. But, I change out half the water every week. So, you can do the math.

10 Tanks (Now 11)

 

[Byron]

First, we/you need to ascertain the parameters of your source water. GH and pH especially, also the KH (Alkalinity) is useful. Adjusting these to provide a healthier environment for certain fish that may have differing parameters is not at all easy, especially for someone new to the hobby. Fish suited to your source water makes their lives and yours much, much easier.

Second, if you intend corydoras catfish, you need a soft sand substrate. Gravel has bacterial issues, plus the possible sharpness, and they cannot filter feed as they should. If you need to change to sand, now is the time to do it before fish are present.

Third, some, in fact most, fish species we keep are shoaling/schooling fish. They absolutely must have a decent-sized group. Ten of the species is about as low as you should ever go, and more will always make the fish happier (whatever "happy" may mean!). And, these should be acquired at the same time. Not only will they settle in faster and be more likely to avoid problems like ich from stress, those species which may have an hierarchy of some sort will be overwhelmingly better.

I understand about the live plants, but the benefit of floating plants cannot be overstated. They suck up incredible amounts of ammonia/ammonium, and they provide shade. And they are easiest to grow.

Last comment...stocking calculators are best ignored. They cannot possibly take into account all the important factors, this take knowledge and thinking on the part of the aquarist. There are many factors to consider.

 

[TheHumm]

I will leave this to someone more experienced.


What are your water parameters? Do you have hard or soft water. That dictates what fish you can keep. You can find this from your local water source website.


I think quarantine tanks are suppose to be void of items, but again, I'll leave this to a more experienced member.





Cory cats need to be in at least a group of 10 or more. Same with the danios and rasboras. Although I think more along the lines of 15 fish per group would be even better.

Thank you for taking the time to reply, and for your insights!

 

[TheHumm]

Hello. Good question. I don't keep small tanks. The smallest I have is 45 gallons. But, if you're willing to change half the tank water every week, you can keep a few more fish than someone who changes the water less often. In one of my 55 gallon tanks, I have roughly 150 small fish. But, I change out half the water every week. So, you can do the math.

10 Tanks (Now 11)

That's consistent with other things I have read--namely, that stocking level affects how often and how large your water changes need to be. Thanks!

 

[TheHumm]

First, we/you need to ascertain the parameters of your source water. GH and pH especially, also the KH (Alkalinity) is useful. Adjusting these to provide a healthier environment for certain fish that may have differing parameters is not at all easy, especially for someone new to the hobby. Fish suited to your source water makes their lives and yours much, much easier.

Second, if you intend corydoras catfish, you need a soft sand substrate. Gravel has bacterial issues, plus the possible sharpness, and they cannot filter feed as they should. If you need to change to sand, now is the time to do it before fish are present.

Third, some, in fact most, fish species we keep are shoaling/schooling fish. They absolutely must have a decent-sized group. Ten of the species is about as low as you should ever go, and more will always make the fish happier (whatever "happy" may mean!). And, these should be acquired at the same time. Not only will they settle in faster and be more likely to avoid problems like ich from stress, those species which may have an hierarchy of some sort will be overwhelmingly better.

I understand about the live plants, but the benefit of floating plants cannot be overstated. They suck up incredible amounts of ammonia/ammonium, and they provide shade. And they are easiest to grow.

Last comment...stocking calculators are best ignored. They cannot possibly take into account all the important factors, this take knowledge and thinking on the part of the aquarist. There are many factors to consider.

Thank your for your thoughtful response. You have given me a lot to think about.

 

[xxEMOxLIZZARDxx]

Thank you for taking the time to reply, and for your insights!

You're welcome!

 

[seangee]

I would recommend a minimum 50% water change weekly, whatever you stock. Personally all my tanks get 75-80%.

 

[10 Tanks]

Hello again. If I may, I'd like to put in a vote for keeping the first tank very basic. I wouldn't fret over the chemistry of the tank water. If you're not keeping and breeding rare fish species, you don't need to worry about a specific chemistry, just keep the tank water clear of dissolved fish waste by removing and replacing a minimum of half the tank water weekly. This will maintain a steady water chemistry and this is more important than a particular chemistry. A particular chemistry is going to be very difficult to maintain and that isn't going to be good for any fish.

10 tanks (Now 11)

 

[AdoraBelle Dearheart]

I think quarantine tanks are suppose to be void of items, but again, I'll leave this to a more experienced member.

That often used to be the way, and many people do try to QT in bare glass tanks - but many of us disagree with that approach. For one thing, it leads to very stressed fish, and pale, stressed fish not only look sickly, but have weakened immune systems, and much more likely to succumb to an illness they might have otherwise been able to fight off.

The main rule really is not to have anything in the QT you aren't willing to dispose of. Fake decor can be easily cleaned so as to be re-usable even if disease occurs, a thin amount of sand or gravel that you never use in your main tanks means fish aren't being stressed/blinded by the lights reflecting from a bare bottom tank, and fake plants and decor give the fish a sense of security. I add live plants to my QT when it has fish, but only spares from fast growing plants like elodea, hornwort, or floating plants, nothing expensive or that I'd put back in my main tanks! Gets disposed of after QT.

Since QT should happen for at least two weeks to a month, having the tank feel like at least a basically decent homely situation for the fish will be much better for them than a completely bare glass tank.

 

[xxEMOxLIZZARDxx]

That often used to be the way, and many people do try to QT in bare glass tanks - but many of us disagree with that approach. For one thing, it leads to very stressed fish, and pale, stressed fish not only look sickly, but have weakened immune systems, and much more likely to succumb to an illness they might have otherwise been able to fight off.

The main rule really is not to have anything in the QT you aren't willing to dispose of. Fake decor can be easily cleaned so as to be re-usable even if disease occurs, a thin amount of sand or gravel that you never use in your main tanks means fish aren't being stressed/blinded by the lights reflecting from a bare bottom tank, and fake plants and decor give the fish a sense of security. I add live plants to my QT when it has fish, but only spares from fast growing plants like elodea, hornwort, or floating plants, nothing expensive or that I'd put back in my main tanks! Gets disposed of after QT.

Since QT should happen for at least two weeks to a month, having the tank feel like at least a basically decent homely situation for the fish will be much better for them than a completely bare glass tank.

Fair enough. I wasn't aware that it is okay to have it lightly decorated. I always thought keeping it bare helped prevent anything from getting in the substrate or on the plants that could impact another fish added later.

 

[Essjay]

If the fish in quarantine are sick, they are usually treated for it. If the treatment is successful there should be nothing left to infect future fish, but if the fish die I would throw anything away that I couldn't sterilise and start again.

I have successfully quarantined fish without mature media, just a lot of elodea (anacharis) left floating and since I don't want that in my main tank I just threw it away after quarantine and put the tank away. I did use a small filter filled with just filter floss to catch any bits and move the water round. Substrate I leave to air dry. Since I rarely add new fish these days anything in the substrate would die out in the months/years between additions but plain gravel or play sand is cheap enough to use new every time.

 

[xxEMOxLIZZARDxx]

If the fish in quarantine are sick, they are usually treated for it. If the treatment is successful there should be nothing left to infect future fish, but if the fish die I would throw anything away that I couldn't sterilise and start again.

I have successfully quarantined fish without mature media, just a lot of elodea (anacharis) left floating and since I don't want that in my main tank I just threw it away after quarantine and put the tank away. I did use a small filter filled with just filter floss to catch any bits and move the water round. Substrate I leave to air dry. Since I rarely add new fish these days anything in the substrate would die out in the months/years between additions but plain gravel or play sand is cheap enough to use new every time.

Fair. I've never understood a quarantine tank to begin with. I always thought it was weird to keep a fish separate while treating it since I'd feel bad for the fish.
Someday I'll set up a quarantine tank. I've got two extra tanks lying around.

 

[Essjay]

These tanks are only used to treat sick fish if something which doesn't spread infects a fish in the main tank. If it spreads, the whole main tank has to be treated.
For quarantine, there's usually a whole shoal of shoaling fish in quarantine waiting to make sure they haven't already got something nasty from the store/wholesaler/importer. Fish that don't need a shoal are OK on their own. They are left in the quarantine tank long enough to spot any illness before they are put in the main tank to spread a disease in there.