I haven't seen eye-to-eye with L75 for a while now. I never really cared for this fish, but now that I work with this fish and uneducated fishkeepers weekly, I really have a loathing for it. In case you are lost, L75 is commonly known as the Trinidad plecostomus (Hypostomus punctatus) or even more commonly known as the Common plecostomus. My frustrations with the Common pleco steam from all of the people who come into work (almost on a daily basis) and tell me "I just started a new tank, I need a pleco", or worse, "I have algae where are your suckerfish?". The Common pleco spans several common fishkeeping myths: All tanks need an algae eater, Bottom feeders don't need to be fed, bottom feeders eat excrement, fish only grow to the size of the tank and, if you write "plecostomus" instead of pleco online, your pleco will die suddenly. The uneducated hobbyist, sees the Trinidad pleco as an excuse to practice poor aquarium maintenance habits. "I don't have to do water changes because my pleco cleans the glass and eats all the fish poop in the tank." The Trinidad pleco will grow to a size of 24" (the full length of a 20g tank) facilitating the need for a tank of at least 150g and it is copious waste producer, so a powerful filter is always required; in most cases, L75 will contribute more waste than it actually "cleans" out of the tank.
The myths about everyone needing a pleco in the tank is so ingrained in the mind of the uneducated hobbyist(I am loath to call them fishkeepers or aquarists) that convincing them otherwise is a chore. Most will not care that the fish's growth will become stunted, in fact, they are hoping for this so they can justify to you that fish grow to their tank size with no ill effects. They will insist that they can not keep the tank clean without one. They will attempt to convince you that when it gets too big they can find someone who will take it. I had one woman go so far as to tell me that she didn't care if she was artificially shortening an animal's lifespan by putting it into a 20g tank because they're cheap enough to buy a new one in a year. This is why I hate the L75, if it didn't exist I would not have to hear people say such repugnant things and I would have to argue with customers and refuse to sell them fish; my day would be a lot less hassle and I wouldn't lose my store so much business.
On a brighter note, you can have an algae eater in almost every size of aquarium available if you expand your horizons. Fish from the Corydoradinae family make great bottom feeders and algae eaters, come in several color morphs including the Lazer Cory, and only grow to around 3". Fish from the Ancistrus family include bristlenose plecos, many of which stay under 6", come in many wonderful colors and patterns, and in my opinion, greatly out preform the Trinidad pleco when it comes to algae cleaning power. I have a 4" female BN pleco in my 55g which sits right next to a sliding glass door and she keeps the whole tank spotless, I never have algae. Snails are another great option for small tanks. I have two apple snails (Pomacea bridgesii) in my 16g tank and they do a wonderful job at cleaning the tank and they actually very active and fun to watch.
It is my hope that if you own an aquarium of any size that you will do some research and educate yourself as to the species available for sale in your area and you will steer clear of L75 unless you have a ]v[onster tank; otherwise take one of my suggestions to heart and pick an appropriately sized specimen for your tank. Remember, a fish (no matter the kind) will ever be a substitute for good aquarium maintenance.