Is my tank overstocked?

[16gallontanker]

In my 20 gallon standard tank I have good filter and I have to clean the filter pads after 2 days. Does that mean I'm over stocked ? In my tank I have 9 albino corydoras, 4 peppered corys, 3 octocinclus catfish and 2 adult dalmatian mollies and several baby mollys and about 6 baby albino corys in the breeder net I rotate the food I give them to a 1 algea wafers or shrimp pellets or some fluval bottom feeder formula granules at least once a day and the top feeders flakes twice a Day I also feed the baby albino some crush led up bottom feeder food

 

[CassCats]

Personally a 20g is small for mollies, they ideally should have a 40g+ because they can get really big for a 20g.


That said even the corydoras you have are a little high in number for the tank size, they too can get 3 inches or more, which is a lot of fish for the tank size. Of the larger corydoras, such as aenea and paleatum, I'd only go up to 8 altogether in a 20g. And I stock generously.

The other thing, is water parameters have very little overlap. Your otocinclus need GH below 215ppm, while mollies need a GH 250ppm+. You should know your GH and stock according to what your tap is, unless you have no issues buying the stuff to adjust the GH for the fish, but then one will suffer either way as there's no overlap on the otos and mollies. The corydoras species you have can handle up to 268ppm GH, but still a very narrow range.


Anyways for size:
This lady we used to have, some can get even larger than her.

And for aenea cory size:

When stocking, you want to factor in the potential max size. Fish sold in stores are often young fish with lots of growing still to do.


Your stock levels, I'd expect in a 40g, a 20g is cramped for these choices of fish, in my opinion.

Mollies also poop a lot lol they're a higher bioload fish.

 

[16gallontanker]

I totally agree but I have to find a way to get rid of mollies I guess once they die I won't be getting anymore because they reproduce too much ill keep the adults till they die though but after that no more.

 

[Naughts]

Although I agree with Casscats, your question was about filter pads and I would say that was an issue with over feeding rather than just overstocking.

You are correctly feeding the babies frequently (maybe 3 times a day) but the adults should be fed less so. Adults are healthy when fed 4 times a week.

The combination of fry in a breeder net and adults in the tank is a conflict of interests. If you could get the fry into a grow out tank that has plenty of food and lots of water changes, this would allow you to restrict feeding in the other tank.

 

[Colin_T]

If you have to clean the filter more than once a month there is an issue. Either too many fish, or too much food, or a tiny filter.

What sort of filter do you have?
Maybe look at adding another bigger filter and keep them both running.

 

[16gallontanker]

I have a aqueon quietflow 10 and I use these pads for filtration and I never clean the bio grids

 

[Colin_T]

Is the filter pad stopping the water flow after 2 days?
It shouldn't block up in 2 days. A small amount of brown gunk on the outside is normal. If the blue and yellow sponges get dirty in a few days then you are definitely overfeeding. But that filter pad should be fine for at least a few weeks and probably a month.

You can replace it with a normal sponge that doesn't have the fine white matt on the outside and that might not clog up as quickly. Just get a sponge that is the same size or slightly bigger than the pad and put it in the tank for a month (preferably near the filter intake or in the filter if there's room). Then get rid of the original pad and leave the sponge there.

 

[16gallontanker]

I feed my bottom feeders twice a day either some 5 to 6 shrimp pellets or a whole algea wafer or some fluval bug bites bottom feeder formula. I feed my mollies tetra colors tropical flakes 2 times a day as well.

 

[Jinx_]

I use a sponge filter because I have shrimps that I want to breed, and once my gups grow up I also want to breed them.

I have to clean it often as well, not sure why. It could be either up to detritus overload, or because it's one of them corner sponges.

 

[Jinx_]

Personally a 20g is small for mollies, they ideally should have a 40g+ because they can get really big for a 20g.


That said even the corydoras you have are a little high in number for the tank size, they too can get 3 inches or more, which is a lot of fish for the tank size. Of the larger corydoras, such as aenea and paleatum, I'd only go up to 8 altogether in a 20g. And I stock generously.

The other thing, is water parameters have very little overlap. Your otocinclus need GH below 215ppm, while mollies need a GH 250ppm+. You should know your GH and stock according to what your tap is, unless you have no issues buying the stuff to adjust the GH for the fish, but then one will suffer either way as there's no overlap on the otos and mollies. The corydoras species you have can handle up to 268ppm GH, but still a very narrow range.


Anyways for size:
This lady we used to have, some can get even larger than her.
View attachment 349592
View attachment 349591
View attachment 349590



And for aenea cory size:
View attachment 349595

When stocking, you want to factor in the potential max size. Fish sold in stores are often young fish with lots of growing still to do.


Your stock levels, I'd expect in a 40g, a 20g is cramped for these choices of fish, in my opinion.

Mollies also poop a lot lol they're a higher bioload fish.

Ohh that's such a beautiful big molly gurl!
I used to have a big sized tank with a few, they were small and once they grew up one became so aggressive and stayed solitary. It was ok tho, she just needed to be alone lol and only was so aggressive when there was someone nearby. Then I quit the hobby due to disease outbreaks.

 

[CassCats]

I feed my bottom feeders twice a day either some 5 to 6 shrimp pellets or a whole algea wafer or some fluval bug bites bottom feeder formula. I feed my mollies tetra colors tropical flakes 2 times a day as well.

That is a lot. You can cut to 1x a day feeding. Some folks have a fasting day where they don't feed, some even do every other. I'm in the feed every day boat, but 2x a day for adult fish is far too much. Growing fry you feed 2x a day generally, but small amounts.

Try to keep in mind, their stomachs are generally the same size as their eyeball, so they don't need a ton of food to get enough to eat.

 

[16gallontanker]

Ok

 

[MaloK]

I have a aqueon quietflow 10 and I use these pads for filtration and I never clean the bio grids

That looks like a very good mechanical filtration, Don't be too surprised if that clogs faster anyway... It removes more for sure. The grade of the sponges looks pretty fine and I wouldn't expect that to last very long between maintenance.

Are the dark layers Activated Carbon ? If it's the case they are probably sold as disposable.

 

[16gallontanker]

It says it can be washed up to 300 times that s alot cheaper than replacing oem cartridges every month

 

[anewbie]

Definitely too many cory in that tiny space. Luckily cory in general get along but i'm not sure i'd put 13 pygmy in a 20 high much less 13 full size cory. Others have already commented on the platy; btw fundamentally platy are polar opposite of cory with regards to water requirement - i.e, platy love hard water and cory love soft water. Well ... 13 pygmy in a 20 high should be ok but still...