Have any of u kept jack dempsy's ive read they dont get as big as the Oscars do how do they do together with the cat fish like u suggested earlier with the pleco in a 100 gallon.... I was planing on a canister filter rated for a 150 gallon ...... Would sand or gravel be better
Instead of thinking in terms of gallons, start thinking in terms of dimensions. 100 gallons doesn't mean a thing (nor is it a size tank that's even available generally). People often will throw around specific size tanks because they are standard sizes that correspond to specific dimensions. For example, a 55 is a 4 foot by 1 foot base. A 75 is also 4 feet, but 1.5 feet wide which is a 50% larger footprint than the 55. So when someone suggests a 75 instead of a 55, they are REALLY suggesting a wider tank - the 20 gallons by themselves don't matter. Another good example is 20 gallon tanks. They can be either 30, 24 or 20 inches long - makes a big difference for a lot of fish so just because you have a 20 gallon tank doesn't mean you can duplicate the stock of someone else's, because they may have a 20 long and you may have a 20 extra high.
My 90 came with a full grown oscar and a JD. The oscar was too big for the tank in my opinion, and the JD was pretty beaten up. I whole heatedly agree that a 6 foot long tank would be best.
You have and want to keep some BIG fish, so you need to get a BIG tank. The oscar will grow FAST - 10 inches within the first year, just to give you an idea. I would not waste money on a tank that you will have to upgrade in a year unless you intended on keeping it.
Canister filter is definitely the way to go, unless you want to do a sump or wet/dry. I have 2 on the 90 and 125 and 3 on the other 125 (the "big fish" tank). I would have only 2 on that one as well, except that I have 2 smaller filters from a tank I tore down that I am using instead of buying a second large filter. On the one 125 I run a sunsun 304 (525 GPH) and an xp4 (450 GPH). On the 90 a sunsun 304 (525) and an xp3 (350). On the other 125 is an xp3 (350), a sunsun 303 (370) and a sunsun 302 (265).
Sand is great.
Show tanks 125, 125, 90, 10, 5, 2.5
QTs 2x29, 2x20