For a filter, just get some elephant ears and plant them in a cheap plastic pot filled with gravel. They grow like crazy and tend to do a better job at keeping the N's in check than other plants. If the N's start to rise when the plants reach relative maturity, cut them off to put them back into fast growing mode. As for fish, I prefer the Western mosquito fish. They are a tad more cold tolerant and can be caught by the bucket full with an empty water bottle and a piece of tortilla.
Here's my stock list that is living in 150 gallons (50 & 45 gal aquariums w/ extra water storage tank/pond),
1x 8 inch Koi
1x 5 inch feeder goldfish
5x 1 inch feeder goldfish
1x 10 inch pleco
1x 3 inch pleco
1x 5 inch bluegill sunfish
4x 1 inch bluegill sunfish
1x 4 inch long ear sunfish
1x 3 inch warmouth
1x 6 inch Rio Grande cichlid
1x 1.5 inch crowntail betta female
1x 4 inch blue gourami
10x 1-3 inch black bullhead catfish
7x fancy guppies, 4 of which are large prego females. Probably around a dozen offspring up to a half inch long.
100+ Western mosquito fish
7x rams horn apple snails with shell diameter over 1 inch
3x 2 inch dwarf crayfish
Countless small rams horn apple snails, MTSs, pouch snails and quilted melania snails.
Yeah, kinda heavy
Until recently I have not had any kind of filter whatsoever besides two old broken HOBs that the overflows go into to remove debris. I did throw some large sponges into the pump's cage in preparation for temporarily holding a legal sized (18+ inch) flathead catfish in the tank but it isn't necessary. I test my water weekly and have yet to have anything but extremely low readings and my water is always crystal clear.
