Kind of Fish for 75. gal ??

Pacus get to big for a 75 and you could keep one oscar but it will uproot your plants. You might be able to get away with some java on driftwood but I wouldn't bother. You could do some severums or angels, maybe three with some dithers like rainbows maybe six bosemanis or guinea reds and a galaxy pleco and raphael cat. If you decide to skip plants it would really open up your options, I mean really there are tons of mating pairs of fish you could put in there... nics, convicts, firemouths, cupids, any of the dwarves (multiple pairs even with rams or a harem with apistos), sajica...or maybe some geophagus....you get the idea.

Severums are great fish. Also if you wanted to do plants a bala shark would look nice. pictus catfish are nice as well, they have a white body with black dots and they only get about 5 in. Most chiclids dont do well with plants

keep in mind though, that bigger isnt always better. i love my oscars, and i filter my tank at about 800gph and its still a mess plan out your tank well

If you want to do large fish and a planted tank, a 75 might be a little small for what you are looking into.
But the fish that would do well in a planted tank of this size would be some angels.

pacus grow way way too fast.

Andy,
Be brave - go for the Oscar! I didn't know what I was getting myself into when I got mine, but I learned fast. They are a pain in the *** but I love mine and he's very entertaining. He's only about 11", but sometimes it's like having a dog.
He will "rearrange" his home as he thinks it should be, and I spend my time moving things back where I think they should go - only to come home and have it different again. They tend to do more rearranging when they are subjected to light. They don't like the bright light (mine during the spring and summer is subjected to early morning sun that shines in his tank for a minimal amount of time. Not enough to "heat" the tank - but enough to tick him off - hence the rearranging). Yes he probably will eat live plants - so that's why I've opted for the "fake" ones in his tank. Not as nice, but less mess and easier to play the "redecorating" game.

Don't put him in the kitchen though! I made that mistake. I store his food in a cabinet where most of my canned goods are and just like a dog - he knows everytime I open the cabinet and he starts flipping and banging around like a mad man thinking he's getting fed. (Also does not like it when I leave the room - will spend his time banging his head against the lid of the tank occasionally to get my attention - "hey! did you forget me in here?")

They are a lot of work - but also can be a lot of fun.
A fish with "attitude" - that's what you need.

Quick follow-up

I also have a cat (rafael) in with my Oscar - works out fine and the cat is about 6" right now. Keep in mind that you won't see the cat hardly ever though (as expected).

Big Fish....!

Hello,

I once had Oscars and a small mouth bass, and a gar in a 55 Gallon tank, I was new to the aquarist community so I didn't now better then to keep fish this size in such a small tank.

I have to agree Oscars are a lot of fun, I am looking in purchasing a 80 or 100 Gallon tank, and guess what fish I'll be putting in them... You guess it Oscars. They are very smart and have a very specific personality unique only to them.

As far as the cat fishes, you have a varity of them to pick from, and here are some which would live nicely in your 75 Gal tank:

1. The Bumblebee Catfish FAMILY: Pimelodidae
SPECIES: Pseudopimelodus raninus raninus, Maximum growth
size 5 Inches.
2. Temminck's Bristlenose FAMILY: Loricaridae
SPECIES: Agamyxis Pectinifrons, Maximum growth size 5.5 "

3. Chocolate catfish FAMILY: Doradidae
SPECIES: Achantodoras Spinosissimus, Maximum gorwth size
6 Inches.

Hope you can get your hands on any of them, 'cause they are very nice fish to have and watch.

Sincerely Yours
Tiburon72