How Many Fish Can I Have in a 75g Tank?
- Thread starter Haylee
- Start date
The Oscar that evolved in the largest river in the world?
The answer is subjective, personally I pity Oscars in 75 gallons. They can grow anywhere from 12 to 17 inches so I don't believe housing one in an 18in wide tank is exactly generous or fair.
They are also a very intelligent species that require stimulation.
I don't believe there is enough room to decorate a 75 to provide interest and stimulation for a full grown Oscar.
most r tank raised now and what most ppl put them in a 75 is fine and not every oscar will exceed 14-15inch
Like I said, subjective subject. You got your view I got mine.
All freshwater fish constantly urinate, mostly thru their gills.
An adult oscar in a 75 gal will be swimming in a soup of urine, unless you do 50% water changes every other day or so.
This leads to hole in the head disease, and other maladies.
I believe keeping oscars in too small tanks is why you see so many people turn scarred and flared gill individuals into LFSs so often.
They are fine when young, but as they grow, chronic diseases are very common in tanks the size of puddles, or ruts in the road, like 75s.
An adult oscar in a 75 gal will be swimming in a soup of urine, unless you do 50% water changes every other day or so.
This leads to hole in the head disease, and other maladies.
I believe keeping oscars in too small tanks is why you see so many people turn scarred and flared gill individuals into LFSs so often.
They are fine when young, but as they grow, chronic diseases are very common in tanks the size of puddles, or ruts in the road, like 75s.
In any suitable body of water, the more that fish biomass increases, the more that growth rates decreases once some biological limit is reached. (Biological limit is set by many variables like ammonia, nitrites, nitrates, food, oxygen, temperature, etc., so this isn't a set number.)
Since, the limit varies by species and water quality, people generally use experience rather than "eye-balling" a tank. One 9" Oscar along with 5 or so fish in the 3-5" range is already a significant amount of biomass in 75 gallons of water. You might get away with several small fish (like tetras), but you may already be seeing the effects in the Oscar's growth rate.
This is of course independent of the impact of aggression and disease, which also increase as biomass density increases. So, overall, this is a health issue.
Since, the limit varies by species and water quality, people generally use experience rather than "eye-balling" a tank. One 9" Oscar along with 5 or so fish in the 3-5" range is already a significant amount of biomass in 75 gallons of water. You might get away with several small fish (like tetras), but you may already be seeing the effects in the Oscar's growth rate.
This is of course independent of the impact of aggression and disease, which also increase as biomass density increases. So, overall, this is a health issue.
Not ideal but not the worst scenario that's for sure.
Don't be overly concerned with some of the other comments.. The fact you've joined this site and asked the question means you want to learn more about the hobby, some people forget that.. However, now you know not to add additional fish!
If not already doing so, buy a test kit and monitor your water, see if your current water changes are keeping the parameters down. If you can maintain low nitrates like previously mentioned you'll reduce stress and increase the health of your fish.
Best of luck.
That's like saying someone is born in prison,so they should live in a box.
Ur not getting the point Im trying to say these fish r used to tanks an Oscar imo with weekly water changes is fine in a 75 with good filtration
Used to? You realize even the captive bred ones are bred in ponds, they aren't used to anything like a tiny tank
