This stylish little tank gives you a lot of bang for your buck ... it is basically an 11 inch cube, which translates into ~ 5.8 gallons overall. The filter chamber takes up about a third of the volume, which is where you end up with the 3.7 gallon number in the description -- it refers to the volume of the display tank. The light is strong enough to grow low- and possibly medium-light live plants. The pump that runs the filter is adjustable, but the flow is still too strong (imo) for fancy bettas. I have used this unit both for a betta and a small colony of neocaridina, with the addition of a sponge behind the filter intake to slow the flow for the betta and prevent shrimplets from getting sucked into the filter chamber. The one real complaint I have about this setup is that the output nozzle does not fit snugly on the elbow that attaches it to the filter hose, causing it to blow off at the smallest provocation, particularly if the filter is on its highest setting. I solved this problem by siliconing the nozzle to the elbow, which was someone unattractive until my plants grew tall enough to hide it.

Whomever selected the current product photo of an empty tank with no light or glass lid really is doing this aquarium an injustice, as it is an amazing value with appealing aesthetics. I own two of these aquariums (purchased locally through Dr. Foster & Smith's sister pet store chain) and recommend this to anyone looking for a nano tank for a betta or a few small fish. Keep in mind that the rear filter area takes considerable space, so the actual size for the fish is more like 2.5 gallons (just an estimate). However, I've found it to be perfect for one male betta fish and a mystery snail along with live plants. Despite the picture, a glass lid and LED light fixture are both included. All you need to purchase separately is a heater (I use a 25 watt Cobalt Neo-Therm placed in the compartment with the pump), substrate (pictured is CaribSea Torpedo Beach), and any plants or decor you like. A water test kit would be helpful as well since nano tanks can easily become imbalanced if not properly cared for with weekly water changes and testing. The LED light is strong enough for low-light plants like moss balls, anacharis, moneywort, hornwort, etc. Since it's a touch light, I haven't been able to get it to work on a timer and am working on purchasing an inexpensive switched LED light that still provides enough light for plants. The rear sump area comes with a charcoal cartridge, bio media cartridge, sponge, and small pump with adjustable flow. I added a Fluval filter sponge to the output to slow the flow even further for my betta. You can adjust the flow angle as well. I have heard rumors that the charcoal filter cartridges have been discontinued, but you can easily use another brand that is smaller or use Poly Filter pads like I plan to use (Poly Filter is available here at DF&S). I also had room in the middle rear compartment for two Marine Pure balls (also purchased from DF&S) for enhanced biological stabilization. With the light, the tank is about 13.5" tall, and it fits fine under our kitchen cabinets. I also own a Fluval Spec III, Aqueon Ascent 6, and a 16 gallon Aqueon bowfront...yet I would still recommend this Imagitarium 3.7 gallon as my favorite nano tank, especially for the price. It might be worth buying two so you have spare parts if anything breaks...and the aquarium is discontinued. For the price, this tank is a handsome bargain.