Hi,

I'm thinking about moving away from keeping snakeheads and Oscars are on my list of potential "replacements" so...

Question 1
The first and most important question I have to ask is: is this tank suitable and if so for how many?

It measures 52"x20"x26" (LxWxH) which equates to about 97.5 UK gallons / 117 US gallons.

It's got my snakeheads in at the moment so it's already cycled and is filtered with a Fluval FX5. It's lit with 2x 4' Marine white T5 tubes.

Question 2
Assuming the answer to question one is positive then I have a query on substrate. I currently use sand and trumpet snails to help keep it aerated. Can I continue to use sand?

I would happily change to gravel, does it have to be of a certain size as I quite like the idea of using fairly large pebbles.

Question 3
Plants - I have quite a few in at the moment, I've read that Oscars will re-arange the tank to suit them. Is it worth leaving the plants in for them to decide whether they want them or is it best to just remove them?

Question 4
Would some large stones to hide behind be suitable or does it need to be a full blown cave with a roof?

You tank would be great for 2 adult O's. I have a question for you though... Do you want to try to breed them? If the answer is yes then go buy about 6 babies and wait until they pair off(will usually be a male/female pair) also note that you are going to probably want these all from different stores to keep from inbreeding. When that happens, find new homes for the ones that your not keeping and go from there.. The sand is great and the O's will eat the snails eventually but probably not until they will fit in their mouths. The plant issue is dead on. However, if you start them out as babies, you may be able to adjust them to the plants. I would leave them in the tank until you decide weather its worth it or not. Large stones are perfect for them. Really though, they dont NEED any decorations.. its more for you to look at than anything else.

Thanks for the reply, I just added a sneaky edit about using gravel as substrate.

I have no intention of breeding. If I kept 2 does the gender matter?

quest 1 that will be ok
quest 2 dont no somebody will be able to help u
quest 3 they will rearange it all i think u will find out if they like it
quest 4 i havent got a cave they can hide as he grown out of the ones i got and mine seems very happy with out one
somebody else will be able to help u abit more than this as there is alot of helpfull people on here that will help u all the best

97 UK gallons would be really good for one Oscar and a few tank mates. Some people may say it's okay to put a couple of Oscars in there but you would be at your absolute limit.

You're the first person who purposely keeps MTS. I got infested with them a few years ago on only managed to get rid of them when I completely change the tank and substrate.

Sand it's fine, it's what I use

Some people keep plants and Oscars together successfully, other times they completely rip go to to pieces, basically it would be trial and error.

Big rocks, small rocks, perfectly okay

Gravel is ok too... search around because there are lengthy discussions on sand vs gravel. I think you want to have a male and female to ensure that they get along better. but I dont know the actual answer to that one...

Your tank will be fine you 2 oscars

I prefer gravel, set up a undergravel filter system with a gravel tidy but have the output from a cannister filter pushing down the UGF uplift tube and you wont have to clean the gravel very often- just to scoop the big bits out

Leave the plants in and see what happens but dont be surprised to come home and find them floating. If the plants are precious to you then remove then to another tank

forget a cave, it would have to be massive for a full grown oscar to hide in, just go for what looks nice. However stick to large stones and make sure they are very stable, a large 1foot long oscar could move smaller stones and if they fall over and hit the glass on the tank there is a possibility of breaking the tank

Thanks for all the replies, they've all been very helpful!

ViolentJ wrote:


Hi hun and welcome.

To answer our question YES it matters... Two males will likely kill each other. 2 females are fine and a male and a female and you could end up with TONS of baby Oscars...

Good luck!

How do Oscars like their water flow? I have an FX5 which has a good flow rate but I also have a SEIO M820 Super Flow (820 gph) that I can use.

Could someone also confirm how much water needs to be changed and how often? I can't seem to find that, I've probably just overlooked it.

Test your water for nitrates every week before a water change. If the result is over 40 you are either overfeeding (feed what they will eat in 2mins once a day for fish 4 inches+) or you need to increase the frequency or volume of water changes

ViolentJ wrote:


I run my 180 Gl with a central-heater-pump cycling 2000liter/H.
And my Oscar seems to like it.
Plus it helps to keep my water free of floating mess.

I change 50% of my water every week and have to vaccuum all the gravel.
But my tank is pretty loaded.