Oscar not growing

[duanes]

I do a 25 per cent water change every week , oscar is about 3 inch whereas the others are 4 plus , the jack dempsey is running things in there dont know if this can affect oscar also

I consider a 25% water change per week on a cichlid tank, about a wimpy as one can get.
By doing such tiny water changes, you leave 75 % of nitrates in the tank, so they will never be reduced, and will only continue to get higher as weeks role on
I do 30 to 40% water changes on my cichlid tanks every other day, in order to change over 100% of these tanks water per week.
The thing about the others growing faster, is that they are Central American alphas, and as such control the chemical make up of the water, in your tank and thus the growth of anything added after them.
I collect cichlids, and when I do, I test the nitrates in the natural waters they come from, I have yet to do a test where nitrates are even slightly detectable.
Below is such a test, nitrate tube is on the right, undetectable

Another factor, is the cichlids like Rocio and Parachromis come from waters that naturally are mineral rich (hardness), high in pH and high conductivity, so species from that type water are often less effected by high concentrations of certain chemicals in their natural waters, they have evolved to grow in spite of that chemical soup.
,
Oscars on the other hand come from soft, mineral poor (in comparison) waters in S south America, and as such have not evolved the tolerance of hard nitrate rich water conditions.
An example of oscar natural habitat below.

But slow growth may be the least of your worries, unless you start making an effort to increase water changes to a healthy level, under elevated nitrate conditions, Oscars are often prone to chronic diseases like HITH as they age.

 

[EricTheRed]

You have already received some great advice here but I do have some additional thoughts. What is the PH of your water? You need to keep it no higher than 7.5 but preferably much lower. Also, an adult Oscar is going to need a 6 foot tank to thrive when properly housed with milder cichlids like Chocolates and Severums, so your tank is way too small in the long run. Also, the aggressive toothy Jag is a poor tankmate for a comparatively defenseless Oscar and will eventually kill the Oscar unless you separate them or get a massive 240G or larger tank. Even then, the Jag may kill the Oscar. In the meantime, your Jag and probably your tough JD are stressing out the Oscar in your small aquarium which is why he is getting sick and not growing. Please consider rehoming the Oscar ASAP to another aquarium with more suitable tankmates or return him to the fish store. Oscars have wonderful personalities but need the proper environment to reach their potential and thrive.

 

[Nickavfc]

Ok thank

I consider a 25% water change per week on a cichlid tank, about a wimpy as one can get.
By doing such tiny water changes, you leave 75 % of nitrates in the tank, so they will never be reduced, and will only continue to get higher as weeks role on
I do 30 to 40% water changes on my cichlid tanks every other day, in order to change over 100% of these tanks water per week.
The thing about the others growing faster, is that they are Central American alphas, and as such control the chemical make up of the water, in your tank and thus the growth of anything added after them.
I collect cichlids, and when I do, I test the nitrates in the natural waters they come from, I have yet to do a test where nitrates are even slightly detectable.
Below is such a test, nitrate tube is on the right, undetectable
View attachment 1517430
Another factor, is the cichlids like Rocio and Parachromis come from waters that naturally are mineral rich (hardness), high in pH and high conductivity, so species from that type water are often less effected by high concentrations of certain chemicals in their natural waters, they have evolved to grow in spite of that chemical soup.
View attachment 1517431,
Oscars on the other hand come from soft, mineral poor (in comparison) waters in S south America, and as such have not evolved the tolerance of hard nitrate rich water conditions.
An example of oscar natural habitat below.
View attachment 1517432
But slow growth may be the least of your worries, unless you start making an effort to increase water changes to a healthy level, under elevated nitrate conditions, Oscars are often prone to chronic diseases like HITH as they age.

Ok thankyou for your detailed reply im new to the game but im learning fast , i do test the water especially ammonia levels il definitely do a bigger water change next time , my filter under the tank is huge and water is clear im determined not to mess up with this , their fins are up and colour is good but im definitely going to do a bigger water change next , thanks for your reply

 

[Nickavfc]

Ok thank

Ok thankyou for your detailed reply im new to the game but im learning fast , i do test the water especially ammonia levels il definitely do a bigger water change next time , my filter under the tank is huge and water is clear im determined not to mess up with this , their fins are up and colour is good but im definitely going to do a bigger water change next , thanks for your reply

Im also carefull not to add any fish not from the same natural habitat

 

[Nickavfc]

You have already received some great advice here but I do have some additional thoughts. What is the PH of your water? You need to keep it no higher than 7.5 but preferably much lower. Also, an adult Oscar is going to need a 6 foot tank to thrive when properly housed with milder cichlids like Chocolates and Severums, so your tank is way too small in the long run. Also, the aggressive toothy Jag is a poor tankmate for a comparatively defenseless Oscar and will eventually kill the Oscar unless you separate them or get a massive 240G or larger tank. Even then, the Jag may kill the Oscar. In the meantime, your Jag and probably your tough JD are stressing out the Oscar in your small aquarium which is why he is getting sick and not growing. Please consider rehoming the Oscar ASAP to another aquarium with more suitable tankmates or return him to the fish store. Oscars have wonderful personalities but need the proper environment to reach their potential and thrive.

Im obviously new to this so i may of housed my fish incorrectly i wish these aquatics give you proper advice in the first place , the main fish i wanted was an oscar but if hes not happy i guess il give him back , thankyou for the advice

 

[Nickavfc]

Im obviously new to this so i may of housed my fish incorrectly i wish these aquatics give you proper advice in the first place , the main fish i wanted was an oscar but if hes not happy i guess il give him back , thankyou for the advice

And also im aware il need a bigger tank i thought id cross that bridge when i came to it , one thing is for sure my ph and kh levels are fine but i think the jack d is making life hard for him and it wont get any easier with the jags

 

[Nickavfc]

I consider a 25% water change per week on a cichlid tank, about a wimpy as one can get.
By doing such tiny water changes, you leave 75 % of nitrates in the tank, so they will never be reduced, and will only continue to get higher as weeks role on
I do 30 to 40% water changes on my cichlid tanks every other day, in order to change over 100% of these tanks water per week.
The thing about the others growing faster, is that they are Central American alphas, and as such control the chemical make up of the water, in your tank and thus the growth of anything added after them.
I collect cichlids, and when I do, I test the nitrates in the natural waters they come from, I have yet to do a test where nitrates are even slightly detectable.
Below is such a test, nitrate tube is on the right, undetectable
View attachment 1517430
Another factor, is the cichlids like Rocio and Parachromis come from waters that naturally are mineral rich (hardness), high in pH and high conductivity, so species from that type water are often less effected by high concentrations of certain chemicals in their natural waters, they have evolved to grow in spite of that chemical soup.
View attachment 1517431,
Oscars on the other hand come from soft, mineral poor (in comparison) waters in S south America, and as such have not evolved the tolerance of hard nitrate rich water conditions.
An example of oscar natural habitat below.
View attachment 1517432
But slow growth may be the least of your worries, unless you start making an effort to increase water changes to a healthy level, under elevated nitrate conditions, Oscars are often prone to chronic diseases like HITH as they age.

Very presumptuous of you to say im not making an effort to do water changes which i do anyway, i test water regularly plus other fish are thriving which people are disregarding

 

[EricTheRed]

Since the main fish you wanted was the Oscar, you could instead rehome the JD and eventually the Jag (assuming the JD is currently the only fish bullying your Oscar and be prepared to also rehome the Jag when he turns into a thug which he almost certainly eventually will) and keep the Oscar. Your Oscar would be fine in your current tank for about a year or so after which the growing Oscar would be happier in a 6 foot 125G or larger tank once it hits the 12 inch mark.

 

[Sinister-Kisses]

Very presumptuous of you to say im not making an effort to do water changes which i do anyway, i test water regularly plus other fish are thriving which people are disregarding

Nothing presumptuous about it. You literally said you only do 25% water changes. duanes is just advising you that such very minimal water changes simply will not cut it.

I do a minimum of 50% on ALL of my tanks every week, and my tanks are lightly to extremely lightly stocked and well filtered. Time to up the ante in your water change routine is the point being made.

You have a South American oscar with Central American species, so not the *greatest* mix. I realize you are new, and we have all made mistakes as we learned...you have asked the question and are receiving feedback to help educate you as you asked. No need to get defensive, just listen and learn.

If your main "want" is the oscar, I'd recommend rehoming all the CA cichlids you have with it and rethinking the stock around the oscar. Honestly I'd just leave him alone and let him thrive in the space by himself without anyone bothering him; with very large and personable fish like oscars and other American cichlid species, having "just one" in a tank is not as lame as you currently might think it is And almost always better for the fish itself, which should be the main focus. Besides, the tank he is in will be too small for him as an adult anyway, he will require an upgrade as mentioned as he gets bigger, so best to leave him as a solo occupant and focus on getting ready to upgrade him.

 

[Nickavfc]

Nothing presumptuous about it. You literally said you only do 25% water changes. duanes is just advising you that such very minimal water changes simply will not cut it.

I do a minimum of 50% on ALL of my tanks every week, and my tanks are lightly to extremely lightly stocked and well filtered. Time to up the ante in your water change routine is the point being made.

You have a South American oscar with Central American species, so not the *greatest* mix. I realize you are new, and we have all made mistakes as we learned...you have asked the question and are receiving feedback to help educate you as you asked. No need to get defensive, just listen and learn.

If your main "want" is the oscar, I'd recommend rehoming all the CA cichlids you have with it and rethinking the stock around the oscar. Honestly I'd just leave him alone and let him thrive in the space by himself without anyone bothering him; with very large and personable fish like oscars and other American cichlid species, having "just one" in a tank is not as lame as you currently might think it is And almost always better for the fish itself, which should be the main focus. Besides, the tank he is in will be too small for him as an adult anyway, he will require an upgrade as mentioned as he gets bigger, so best to leave him as a solo occupant and focus on getting ready to upgrade him.

Thankyou