Oscar tank 107 gallons

[Rusty91]

Hello together,

my name is Lukas and i m new to this forum. 1 month ago I set up my first Oscar tank.
2 Oscars (2-3 inch)
2 green terrors (2 inch)
1 Pleco (2 inch)
Tank size: 107 gallons

Ph: 7,3-7,5
KH: 12
Temperature: 24-25 Degrees
Nitrite: < 25
Im not sure why I have
this much nitrite
Nitrate: 0

Filtration:
Eheim 2275 professional 4+ 600 (1250l/h)
Juwel Bioflow internal filter (1000l/h)

Maybe you can give me some advice, what I should change or if everything is fine with this setup. I dont plan to upgrade the tank in the near future.
Please be fair, I just started and tried to inform myself as best as possible ?

 

[Rocksor]

Once all those fish are 9-10 inches total length, your tank will require more than 50% water change every 7 days (at least 50% every 2-3 days).

Since you have nitrite and 0ppm nitrate, your tank is still cycling. You need to use a liquid test for ammonia and nitrite, and both should not go higher than 0.25ppm. I would research how to do a fish in cycle.

 

[FLA]

I would drop the Green Terrors. You will see much more satisfying behavior out of the oscars when they grow up. I know the tank looks empty now, but everything will grow fast. If you feel like you have to have something else in there I would look at some convicts or rainbow cichlids. If everything grows up together you might be ok. If you want to try some dither fish to add complexity a big shoal of tiger barbs, fillamentosa barbs, or giant danios would be nice. Some will get eaten, but if you start now you will have some make it.

 

[Rusty91]

Once all those fish are 9-10 inches total length, your tank will require more than 50% water change every 7 days (at least 50% every 2-3 days).

Since you have nitrite and 0ppm nitrate, your tank is still cycling. You need to use a liquid test for ammonia and nitrite, and both should not go higher than 0.25ppm. I would research how to do a fish in cycle.

Thank you for your answer. Im doing waterchanges every 7 days (50-60%), so that will be fine for me if I have to do this when they are bigger.
I startet to cycle the tank 2 months ago and put in the fishes one month ago. So a tank needs to cycle more than 2 months? Seems like I had the wrong information about that. I will definitely research that.

 

[esoxlucius]

Welcome to the forum Rusty91 .

You say you have no plans to upgrade in the near future? I'm afraid if that is the case you are going to encounter some real issues, and due to that selection of fish being quite fast growers, your issues will start faster than you think.

You need to get a handle on your parameters. Ammonia AND nitrite must be 0ppm at all times, and your nitrate should fluctuate up and down between water changes, ideally never going above 20ppm.

Your water change schedule at the moment seems pretty good ( though your nitrate reading will be a better judge of that than i). As those fish quickly grow your schedule will have to change as the bio load increases.

If an upgrade is definitely not on the cards, and you aim to keep all of that stock in a 107g tank then you may be looking at huge water changes every other day, not to mention potential aggression issues too.

I wish you luck.

 

[Rocksor]

Thank you for your answer. Im doing waterchanges every 7 days (50-60%), so that will be fine for me if I have to do this when they are bigger.
I startet to cycle the tank 2 months ago and put in the fishes one month ago. So a tank needs to cycle more than 2 months? Seems like I had the wrong information about that. I will definitely research that.

Your tank is fully cycled if ammonia and nitrites are 0ppm everyday, and you have nitrates reading. Nitrates should be less then 20ppm at a minimum everyday. As they grow, you need to test nitrates at least 2x a week. Within 1 year, you will find yourself doing more than 50-60% water changes every 7 days.

 

[Rusty91]

so u guys think if I take out the 2 green terrors, it will be fine?
Or is 2 oscars and 1 pleco also too much for 107 gallons?
I informed myself about oscars and most of the sites where i searched for the requirements said that 100 gallons are enough for 2 oscars. ?
The problem is, that i dont have enough space for a bigger tank.
So i got 2 options which would be possible:
First one -> take the 2 green terrors out
Secont one-> would be my favorite if it makes sense. Buying better and bigger filtration? Could this help out?

 

[esoxlucius]

Thank you for your answer. Im doing waterchanges every 7 days (50-60%), so that will be fine for me if I have to do this when they are bigger.
I startet to cycle the tank 2 months ago and put in the fishes one month ago. So a tank needs to cycle more than 2 months? Seems like I had the wrong information about that. I will definitely research that.

You have been misinformed regarding the timescale on cycling an aquarium. No one can say it will take 3 weeks, or a month and a half, or 2 months, or whatever. An aquarium reaches its full cycle when ammonia is 0ppm, nitrite is 0ppm and you start to get a showing of nitrate. And that timescale differs from tank to tank depending on the hobbyists method of cycling. Then and only then is your tank nearing something like a full cycle. Research the nitrogen cycle, there's masses of info on line.

You don't mention ammonia (though I suspect it will be 0ppm to low, going off your nitrite reading). And the fact you have slight nitrite and zero nitrate proves you tank is still cycling. Adding those fish was a mistake as they will put a burden on your very young and not yet fully established bio side. But you weren't to know, like I said, you were misinformed.

Keep an eye on those fish for signs of stress, you are at a very crucial stage. But even better, i'd thin out your stock now, rather than have a big headache later.

 

[Rusty91]

You have been misinformed regarding the timescale on cycling an aquarium. No one can say it will take 3 weeks, or a month and a half, or 2 months, or whatever. An aquarium reaches its full cycle when ammonia is 0ppm, nitrite is 0ppm and you start to get a showing of nitrate. And that timescale differs from tank to tank depending on the hobbyists method of cycling. Then and only then is your tank nearing something like a full cycle. Research the nitrogen cycle, there's masses of info on line.

You don't mention ammonia (though I suspect it will be 0ppm to low, going off your nitrite reading). And the fact you have slight nitrite and zero nitrate proves you tank is still cycling. Adding those fish was a mistake as they will put a burden on your very young and not yet fully established bio side. But you weren't to know, like I said, you were misinformed.

Keep an eye on those fish for signs of stress, you are at a very crucial stage. But even better, i'd thin out your stock now, rather than have a big headache later.

mybe it would make sense to buy starter bacteria to help out?

 

[esoxlucius]

mybe it would make sense to buy starter bacteria to help out?

People seem to give mixed reviews on bottled bacteria. Actually I don't think you are far off being cycled. For now though DO NOT feed your fish and like I said keep an eye on them for signs of stress. And monitor your parameters.

As regards to stocking, hmmm, you're going to be dissappointed. Let's just say that the common concensus on this forum, regardless of what you've read elsewhere, is that ONE adult oscar, for life, requires a minimum tank size of around the 120g mark (4x2x2). We put fish first on this forum and our advice reflects that.

If you want to overstock, that is your call, but your water change schedule to keep those fish healthy will be intense. And crowded conditions can lead to stress for your stock, and stress leads to ill health.

You've a lot of decisions to make, I hope you make the right ones, good luck, and again welcome to the forum.