“How much has my cichlid grown?” You ask yourself this question when you look at your tank frequentley. Using a ruler is simple, you can determine length easly. That only shows half of the picture. To know how healthy the cichlid is mean knowing its weight. Knowing how length relate to weight give you more accurate information. This turns guesswork into accurate care.
Using this formula, we created a chart (above) that relates mass to size for 12 popular species. Keep in mind, just because a fish is long doesn’t mean it’s healthy. A stretched-out appearance indicate something may be wrong, either poor nutrition or hidden parasite are likely suspects. If you want a quick snapshot of how your fish is doing (thriving or just surviving), refer to condition factor in the guide. Think of it as a body mass index for fish, is it a healthy combination of length and weight?
Why Weight Matters for Fish Health
When most hobbyists use this method, it’s reactionary; they wait until they see trouble and then respond. Using these charts are proactive. It makes you think and begin taking measurements each month to confirm that your fish are livig well… Not merely growing well. A long fish means nothing if the weight-to-length ratio decline. Something is amiss with either diet or water chemistry. Thinking ahead avoids problems before you can see them.
Surprisingly, body shape enters into these equations. For example, a deep discus is denser than a long pike or arapaima. These fish is long and slender. They have little bulk in every millimeter of their length. To emphasize this, the infographic classifies species according to there physical form. Long, skinny fish has smaller exponents for weight than short fat ones. In other words, their weight doesn’t scale as rapidly with length.
If you assume all fish weigh the same based off length, you could of end up either overfeeding or underfeeding your fish without knowing it. This happens when you don’t consider the biology of what you’re feeding. The most difficult aspect of this is to reduce stress on the specimen as much as possible when measuring. Don’t reach in a net and pull it out hoping for the best.
If you’re using a scale that measures in water bags, that’s great for smaller specimens. First weigh the water and bag so the scale tares correctly. With bigger ones, try to keep the fish calm and supported by use a tray method of measurement. The best case is to get it off the scale as soon as possible without wearing out the animal. As cortisol increases due to stress, the weight may be off momentarily. In addition, it will impact overall health. Be patient now and you’ll save yourself grief down the road.
But here’s where it gets real after you’ve got the numbers. A lot of medications is prescribed based on body weight (in grams). If you’re off by even just a few gram, medication can be as poisonous as it is curative. The reference tables offer estimated weights for common sizes so that you can at least have a starting place from which to compare your own measuring.
If your betta comes in much lighter than the table predicts for its length, then it might be time to start looking at their diet and/or tank condition. Over the years you can look at these numbers and see trends that aren’t seen with just a single number reading. For instance, juveniles will grow in girth (weight) quicker then length as they bulk up into their bodies. Adults tend to keep those two curve closer to each other. Senior fish often lose weight but not necessarily size. This is a normal sign of age, but it is something that should be tracked too. Knowing when your fish are at what stage allow you to manage care and expectations to match.
I’m not suggesting you should become a mathematician of your own aquarium. I’m suggesting that you gain a much better understanding of what’s going on below the surface. By performing simple length checks from time to time while occasionally verifying their weight, you establish a strong health profile for each of your resident. They’ll be healthier, display greater amounts of energy and show better color. Don’t merely see size when looking at your tank. See condition.
