Will Extra Filtration Compensate for an Overstocked Tank?

[chub04]

If you have an overstocked aquarium would adding extra filtration compensate for overstocking? As long as the fish don't seem stressed from overstocking?

I have fancy goldfish, dojo loaches and cory cats in my tank. According to aqadvisor.com my 75g stocking level is at 135% and recommends 50% water change per week. My current filtration is two Marineland Penguin 350s and two sponge filters. I recently added one Marineland penguin 100 as a little extra filtration, but also to build up beneficial bacteria on an extra filter to put on a quarantine tank when needed. I usually do at least 50-70% water changes each week and my ammonia and nitrites are always at 0 ppm and nitrates never above 20-40 ppm, but on average around 10-20 ppm. (side note, I've also modified my filters a little to help house more bb).

That being said, as long as my fish don't seem stressed, would it be okay to keep my tank at this stocking level? I plan on eventually either getting rid of some of my fish or getting another tank to split them up (if I can find room in my house for another tank).

 

[dougall]

If you have an overstocked aquarium would adding extra filtration compensate for overstocking? As long as the fish don't seem stressed from overstocking?

I have fancy goldfish, dojo loaches and cory cats in my tank. According to aqadvisor.com my 75g stocking level is at 135% and recommends 50% water change per week. My current filtration is two Marineland Penguin 350s and two sponge filters. I recently added one Marineland penguin 100 as a little extra filtration, but also to build up beneficial bacteria on an extra filter to put on a quarantine tank when needed. I usually do at least 50-70% water changes each week and my ammonia and nitrites are always at 0 ppm and nitrates never above 20-40 ppm, but on average around 10-20 ppm. (side note, I've also modified my filters a little to help house more bb).

That being said, as long as my fish don't seem stressed, would it be okay to keep my tank at this stocking level? I plan on eventually either getting rid of some of my fish or getting another tank to split them up (if I can find room in my house for another tank).

When it comes to stocking, there are a couple of things things to take into account

• Crowding Levels - Are the fish going to have enough room to move around, turn around in the tank, that sort of thing.
  • That sort of includes - will territorial fish have enough space to claim a spot of their own, and will you have gaps in the line of sight
• Mechanical filtration - will the filter be able to keep up with the amount of poop and stuff , if there's not enough flow, the dirt might settle down on the substrate etc, so more to do vacuum-wise at water change time
• Biological filtration - This will equate to the amount of nitrates that end up because of the number of fish in the tank. This can also be handled by water changes to keep this number down in safe levels, the number and size of them you are willing to do will also let you define stock levels accordingly.

In short, if your fish seem fine, your water test results and how clean your water looks should answer your questions.

 

[SnakeIce]

The nitrogen cycle is either in full function or it isn't. Adding additional filtration only spreads that production level around. Redundancy of filters is an advantage, because if one fails to operate the other has a head start on keeping sufficient numbers of bacteria alive for your tank's waste production.

But filtration does not remove waste, only collects larger pieces and converts it to a less toxic form. Over stocking means you have to do large water changes more frequently. And should something happen like a power outage, you will have to be very prompt in providing alternate circulation methods because the safety margins are much smaller. The cycle bacteria can be found on every surface in your tank with access to flow. So should the power go out I would recommend having a battery powered air pump and air stone as a back up if you don't have a generator to keep the filtration running.

That much stocking also removes minerals in the water faster, which is the second reason to need to do large water changes more frequently in order to replace what is used up.

 

[OrionGirl]

The consequences for an unexpected change are the real concern. If something happens and you can't do water changes, or the power goes out, your tank is less likely to handle it. I normally do weekly water changes, but recently had to cut back to every other week for an extended period of time. All my tanks are planted, and lightly stocked, so this wasn't a problem. Without the buffer space, the potential for a crash is higher.

 

[FreshyFresh]

Chub, exactly how many fish do you have in this 75g? I'm not a big marineland/penguin bio-wheel filter fan, but if what you've got is working for you, stay the course. Your water testing and the health of your fish will tell you. Very cool you've got dojo loaches!! I tried to find them for my goldy tank, but they're banned from sale in my State due to being on the "invasive species" list.

FWIW, I keep 3 fancys, a comet and 3 platys in a 55g, with a sponge filter and an AquaClear 110. This tank also has a pothos plant growing out of it. I do a weekly 75+ % water change on it even though nitrates are still below 20ppm on day 7.

 

[chub04]

Chub, exactly how many fish do you have in this 75g? I'm not a big marineland/penguin bio-wheel filter fan, but if what you've got is working for you, stay the course. Your water testing and the health of your fish will tell you. Very cool you've got dojo loaches!! I tried to find them for my goldy tank, but they're banned from sale in my State due to being on the "invasive species" list.

FWIW, I keep 3 fancys, a comet and 3 platys in a 55g, with a sponge filter and an AquaClear 110. This tank also has a pothos plant growing out of it. I do a weekly 75+ % water change on it even though nitrates are still below 20ppm on day 7.

I've got one ryukin, two telescope, one comet, 3 dojos, and 4 cory cats. So 11 total at the moment in my 75. A few days ago I bought another ryukin from my LFS, I wasn't planning on getting one, but this was an awesome tri colored ryukin and I couldn't pass up on it. Right now he's currently in a quarantine tank, but I'm trying to figure out what I should do with him after he's done quarantining. Put him in the 75 or get another tank. And that's what sparked my question for this thread. (ps that stocking level I mentioned above from aqadvisor includes my new ryukin).

The only adult sized fish in there is the comet, I've had him for 5 years. The rest are still pretty small. Once they start to get bigger I plan on getting another tank for sure.

And the Dojos are awesome! It's too bad you can't get them. They'll come lay in my hands and get so excited when I'm around the tank!

 

[FreshyFresh]

I dunno the bio load and tank requirements of the dojos, but it's often said that fancy goldfish are 20g for one fancy and add 10g for EACH additional fancy. So 3 fancys would be OK in 40gallons, so IMO, with 75g, you're ahead of the game there. The problem could be the comet. Most will say they require a pond, not a tank. I don't disagree with that, but there's LOTS of factors at play that will determine how fast and how much they grow. I've had my beautiful orange comet for 3yrs in an unheated 55g. I've added other goldfish with him over time (3 fancys). The tank stays room temp that can vary from ~67-78F depending on the season and room temp. I feed various pellet, freeze dried and flake foods 5x a week and the comet is about ~7" tip to tip. Two of my fancies are large meatball sized and one smaller. Be careful buying fancies based on color. My red/tiger fancy turned all white after about two years and my grey pearlscale oranda is turning orange! So far my big red cap oranda and orange comet's colors have not changed.

 

[FreshyFresh]

I dunno the bio load and tank requirements of the dojos, but it's often said that fancy goldfish are 20g for one fancy and add 10g for EACH additional fancy. So 3 fancys would be OK in 40gallons, so IMO, with 75g, you're ahead of the game there. The problem could be the comet. Most will say they require a pond, not a tank. I don't disagree with that, but there's LOTS of factors at play that will determine how fast and how much they grow. I've had my beautiful orange comet for 3yrs in an unheated 55g. I've added other goldfish with him over time (3 fancys). The tank stays room temp that can vary from ~67-78F depending on the season and room temp. I feed various pellet, freeze dried and flake foods 5x a week and the comet is about ~7" tip to tip. Two of my fancies are large meatball sized and one smaller. Be careful buying fancies based on color. My red/tiger fancy turned all white after about two years and my grey pearlscale oranda is turning orange! So far my big red cap oranda and orange comet's colors have not changed.

 

[chub04]

I dunno the bio load and tank requirements of the dojos, but it's often said that fancy goldfish are 20g for one fancy and add 10g for EACH additional fancy. So 3 fancys would be OK in 40gallons, so IMO, with 75g, you're ahead of the game there. The problem could be the comet. Most will say they require a pond, not a tank. I don't disagree with that, but there's LOTS of factors at play that will determine how fast and how much they grow. I've had my beautiful orange comet for 3yrs in an unheated 55g. I've added other goldfish with him over time (3 fancys). The tank stays room temp that can vary from ~67-78F depending on the season and room temp. I feed various pellet, freeze dried and flake foods 5x a week and the comet is about ~7" tip to tip. Two of my fancies are large meatball sized and one smaller. Be careful buying fancies based on color. My red/tiger fancy turned all white after about two years and my grey pearlscale oranda is turning orange! So far my big red cap oranda and orange comet's colors have not changed.

Oh I've definitely experienced color change in one of my telescopes. He is (or was) a butterfly panda, really cool black and white colors, 2 months after I bought him and he's nearly lost all of his black. Almost completely all white now. But so far all my others have stayed the same color. Although my comet used to have a little black mustache, but it went away the bigger he got. But it sounds like we have the same comet ha. Mine is also orange, and about 7" tip to tip. But I wish I had somewhere bigger to put him.

 

[SantaMonica]

The limitation in over stocking is ammonia. Feeding fish turns into pee (ammonia/urea); canisters and floss/foam do not remove ammonia, and water changes only remove a little bit that day. For most FW tanks, the only ammonia removal comes from bacterial growth on solid surfaces, and you need a lot of that surfaces (and time for growth) to get the ammonia consumption up.

 

[OrionGirl]

Ammonia is definitely NOT the only issue to address in stocking concerns. Stock levels must take into account the adult size and behavior of the animals in questions. There are many large cichlids that will claim an entire 150 gallon tank and kill anything else that is added with them. Nothing to do with ammonia. Just as some fish will be stressed when kept alone, some will be stressed when kept in groups, or with other species. Some fish wage biological warfare--they produce chemicals which will stunt tank mates. This can't even be tested for by the average hobbyist. Over/under stocking has many factors. Addressing the nitrogen cycle is just one piece.