Choosing Your Tank: Rim Vs Rimless (Part 3)

Today tanks are very commonly sold in one of two principle constructions. Those constructions are rimmed and rimless tanks. Neither of these tanks are inherently superior to one another. The truth is when constructed appropriately, both tanks are more then capable of reliably serving the needs of the hobbyist. Though a hobbyist can find a high degree of success with both types of tanks, there are situations where one type of tank is favored over another because of the advantages that it offers. Finally there are situations outside of the hobby where one type of aquarium offers advantages over the other. This article will examine both types of construction and both the advantages and disadvantages inherent to each.

 We are going to start with the most traditional form of aquarium.  That form is the rimmed aquarium.  The rimmed aquarium usually has two rims on it.  The first is located at the bottom of the tank and the second lines the top of the panels.   These panels are usually grooved in such a way that the bottom rim is where the base panel sits upon.  The bottom rim is designed to take the pressure of the mass of the entire tank, reinforce structurally the bottom of the tank to prevent warping, and finally to distribute the force of the mass among the rim points that the aquarium sits upon.  The top rim of the tank has two main functions as well.  The first function is it is the point where the lid can fit securely upon.  The rim itself is usually grooved in such a way that the glass fits securely into it.  The second function is that it structurally reinforces the glass panel.   This prevents bowing at the top and reduces the pressure placed upon the silicon sealant from the force of the mass of the water pushing against the panels.  The top rim accomplishes this by holding the aquarium together.  The structural supports both top and the bottom are also important when moving the tanks.   Movers will tell you that moving with a rimless tank is very risky as many of those tanks end up failing after the move.   Rimmed tanks on the other hand have a much reduced rate of failure when set up immediately upon settling down from a move.   This is their principle advantage, the structural support that they provide makes them more durable and more resilient with a reduced rate of structural failure.  The drawback to a rimmed tank is really simple.  It is the aesthetic that some people view as ugly, distracting, and less modern.  Detractors to this type of aquarium will point out that aqua scaping contests at large scale aquarium conventions rather unanimously pick rimless tanks for their contestants to demonstrate their artistic and functional prowess upon.  Additional criticisms of this type of tank is that it can be hard at times to see the water level that the tank is at as the top black rim can obscure ones view of the filled water level and that the aquarist has to bend to unnatural angles at times to see the water level as it is being filled.  As of 7/29/26 a rimmed Aqueon 75 gallon tank is comparatively cheap and you would expect it to cost you $180.00 brand new.

 Rimless aquariums are the more modern take on the housing of our aquatic life in he hobby.  This type of aquarium could be acrylic or it could very well be made in the traditional way with multiple panels of glass held together with silicon sealant.  In function the rimless aquarium when built correctly it is every bit as reliable as a rimmed aquarium.   The only real drawback that I have seen is that snails especially tend to crawl up, escape, and die dried out around the tank.   The lack of an upper lip is the only principle cause of this.  I want to stress that from the standpoint of keeping shrimp, fish, and plants there is no real difference between the types of tanks.  Its only with snails that I have noticed a real meaningful difference in function.  The advantage of this type of tank is primarily aesthetic.  Many people including professional aqua scapers find the look or a rimless tank more aesthetically pleasing.  The minimalist nature also allows for better monitoring of water levels as you get to the top.  Unlike rimmed tanks, rimless tanks always display the water level at all angles to the tank.   This makes the maintenance itself a lot easier to do as you have a greater sense as to where the water level is reaching to at all times.   The one possible disadvantage to this type of tank that I was made aware of came from professional movers who alerted me to the fact that in their experience these types of tanks do not travel well.  Traveling long distances without those rims along the base and the top can sometimes structurally damage the tank causing catastrophic leaking.  That being said I personally traveled from Oklahoma to Florida with a rimless cube tank and the result six years later is a tank that has not failed, does not show any sign of being damaged in any way, and remains to this day my favorite tank inside of my fish room.  The only other disadvantage that I see with this type of tank is that its a bit more niche.  This means that your not looking at a traditional aquarium manufacturer like say Aqueon and as a result it is much more expensive.  A quick look online as of 7/29/26 reveals that a rimless UNS 75 gallon aquarium would cost much more then an equivalent 75 gallon tank at $770.  

 So where do I stand on this.   In thirty-five years of experience keeping fish I have yet to see one significant advantage to rimless tanks.   Indeed with money as tight and budgets as strained as they are right now, I find a lot more sense in spending as little as you can on luxuries that don't really matter to the fish, shrimp, or the plants that you keep.   The argument that rimmed tanks can be a little harder to maintain I actually find to be a legitimate point as I have tanks stacked on racks in my fishroom and have had to bend down many times to see the water level on the lower levels.   I don't ever have this problem with my rimless tank.  Whereas I have several times nearly overflowed my bottom level rimmed tanks, I have never had that happen in my rimless tank.  This is not a coincidence although its also not an apples to apples comparison as the rimless is not at the bottom level and the rest are very much at the bottom and on stacks.   Are rimless tanks prettier tanks?  I think that is very debatable as well.  I happen to agree with people who state that rimless tanks are more modern, and more pleasing to the eye.  That being said each one of my rimmed tanks are also labeled with the species kept and the data that I find important in them.  The top rim provides me a very convenient location to place a label upon when I feel the need to do so.  Its also makes a highly visible to contrast the label upon.  As I am advancing in age I find this to be very convenient to my eye.  As such I don't find the top or the bottom rim to be all that unappealing as they offer some utility as well as places of high contrast.  So in closing, I don't find much difference between rimmed tanks and rimless.  If you have the opportunity to acquire either brand new or on the second hand market and at a significant discount I wouldn't hesitate to do so.  What is key is that you do what makes sense to you.  If it will allow you to enjoy your tanks more go rimless, if on the other hand you don't care about the rims and your instead going to focus upon what is inside of it, then you will save a lot of money by going with a rimmed tank.