UnderGravel Filter?

[ChoclateBetta]

If anything hang ons are better.

[bryanacute]

Oh hey CB ur back! And I've decided to wait a while for te filter.

[ChoclateBetta]

Yeah I am still upset about what happened.

[TheCheese909]

Kuronue is very right and gives great information.

I disagree with ChoclateBetta about the long finned fish though. Many long finned fish have problems with mounted filters, the intake can (not will, some intakes are different) shred finnage if it's not covered properly and the outflow will easily toss Halfmoons and such around if it's too strong.

Undergravel filters can help in many ways in addition to a carbon filter. I've never once heard of a fish getting torn up because of an undergravel filter. It's basically just bubbles in a tube, pretty harmless. They are nothing like carbon filters mind you but Kuronue gave all the information you really need for comparing the two.

I've used undergravel filters in my smaller tanks of 2 gallons or 1 gallon, they are great for medicating or quarantining a fish.

[Fishehgobloop]

I agree with Cheese. I've used undergravel filters in quite a few of my tanks, and i never had any problems. All of the torn fins due to filters I've had were with the ones that hang over the side, such as the Top Fin brand filters that usually come in starter kits for 5 and 10 gallon tanks. I've used undergravel filters in one gallon hospital tanks, for sick fish, I have had a couple of fish who lived in 1-2 gallon tanks with undergravel filters as their only filter. With proper water care, they work great in the smaller tanks.
In a larger tank, I wouldn't recommend having an undergravel filter as your only filter. If you have a sorority, I am assuming you have at least a 5 gallon? Though hopefully it's a 10 or more. If so, Tetra brand makes an awesome line of filters called "Whisper" power filters. They start out with a little bubbly filter that's good for smaller tanks (1-3 gallons) and go up from there. They are quiet internal filters, with a moderate outflow, that won't give your fish a hard time when it's swimming, and they're nice and quiet. I use the Whisper filters in 95% of my tanks (excluding my cichlid tank and my Plakat Betta's tank) and I highly recommend them.

[ChoclateBetta]

Not all hang on filters are high current Carter has a standard one. Sponge filters are better than undergravel. I tried a whisper filter in my ten gallon too big and powerful.

[TheCheese909]

You may have purchased the wrong size. I have 3 of them, two of them are in 5 gallons and one is in a 10. They have switches on the back so you can adjust how powerful they are. The two 5 gallons have halfmoon males, they have no trouble what so ever with the outflow, they don't get pushed around even in the least bit. And my 10 gallon has a veiltail who loves playing in the outflow and it's at it's highest setting. It doesn't throw him around at all, it gives him great exercise too even though the tank is big enough for him to not have an issue with exercise.

[ChoclateBetta]

They encourage bacteria buildup from what my book on guppies says its bad for long finned fish.

[TheCheese909]

Unfortunately many books about fish have incorrect information. I've read a handful of books about Bettas and other fish and I always see tons of wrong information. I've never heard of undergravel filters being bad for fish with long fins, I've never had a problem with them and I've never seen or heard of anyone complaining about having any problems with them.

Any type of filter is better than no filter at all. Since this thread is about a sorority tank we don't have to worry about finnage anyway. In a sorority tank you really should have some sort of filter whether undergravel or mounted, there should be some sort of something in there. A true filter, like Fisheh said, would be the best since there are multiple fish in the tank.

It's all up to the OP on what filter to get but I do love the Whisper filters. I have three of this filter (http://www.walmart.com/ip/Tetra-Whis...-1-ct/10291764) in my tanks, it's super quiet. These tanks are actually in my bedroom and I don't hear them at all at night when I go to sleep. They have adjustable settings so you can have it on high or low or inbetween so it doesn't throw your fish around. I don't know what size aquarium the OP has but if it's larger than 10 gallons they have one that looks exactly the same but is slightly larger and is good for I believe up to 20 gallons. It's a fairly inexpensive filter and it's filter pad replacements are cheap as well.

[ChoclateBetta]

Its the animal planet book on guppies. Written by a person who takes guppies to compete and breeds high quality.