We’ve been introducing new life into the tank and I’ve noticed a trend which I thought I’d share with the blog. Feeding the tank is always a concern when working with reef aquariums. With fresh water aquariums, you can usually just throw a bit of food in every day and the tank will take care of itself, since there’s already a lot of algae and other natural growth associated with healthy fresh-water tanks.
But with salt water tanks, over-feeding the tank can have deadly consequences. It was the buildup of ammonias due to exactly this type of over-feeding that partially contributed to our melt-down. It was also this concern that led me to post my most recent post on “building from the bottom, up.” For the sake of water-chemistry alone, you need to avoid over-feeding.
But the trend I’ve noticed is that not only do you not want to over-feed, you actually want to go to some lengths to assure that there is always a need for more food. As concerned aquarists who’ve invested a lot of time and money into our tanks, it is entirely normal that we tend to want our tanks in optimum performance, and so the tendency is to want to assure yourself that everything in the tank is getting fed exactly the right amount.
This is a nice instinct, but not one that squares with the reality of a natural reef environment. Life is struggle, and for marine life, that struggle is the constant quest for the next meal. That’s as evidenced by the fact that there are so many more numerous species of heterotrophs, or animals, than vegetable autotrophs in the marine environment. Plants can make their own food by photosynthesis, but most things in the water need to actively seek out their next meal. They are geared towards this quest, their bodies optimized to go without food most of the time and feed when food is available.
So if they aren’t given that impulse to actively hunt for food, they aren’t going to be very healthy, actually. Precisely the opposite of what we tend to think. Since we’ve added in the new clown fish, we’ve not bothered to increase our feeding cycle at all. The result has been that our diamond goby has been much, much more active and looks a little better. The snails and crabs are constantly working overtime to get their own sustainence. The sand is constantly cleaned by the goby’s activity and the entire tanks is generally more enjoyable to look at.
Best of all, when the goby filters the sand, he kicks up a lot of uneaten food which the ocellaris gets a second crack at. This is the kind of semi-symbiosis that you’re looking for in a tank: let the life that’s there do the work of feeding itself.
So, how much is enough? Well, that’s not an easy question to answer. Another ripple in the current tank’s setup is the introduction of more copipods, which of course represent a constant, reproducing stream of food for the fish, and one that is basically invisible to us humans. How do we know we’ve got enough in the tank when we can’t see them?
You have to just go on what the fish look like, I suppose. If your fish are getting a little thin or if feeding time is particularly aggressive and includes a lot of fighting, then perhaps its time to increase the load slightly. Or perhaps the frequency of feedings should be increased and the amount per feeding decreased, but it’s all going to be instinct that guides you. It’s your tank and they’re your fish, so only you are really going to know how things really work in your little marine universe.
About the only potentially helpful guideline I could suggest would be to consider your tank in terms of those “bottom up” strata I discussed in my earlier post, along with considering a kind of “aggression strata” as well. High-swimming fish such as clowns, called pelagic fish, are going to get first-crack at the food, whereas bottom-feeding gobies, known as benthic fish, won’t tend to get the food till it’s on the bottom. That’s one strata. The other is aggressive fish such as tangs versus passive fish such as dragonettes.
If you have a mix of these types of species, you might want to consider feeding more than once a day so that the aggressive fish get their fill and the passive fish can feed later. You’d want to limit the amount of food in each feeding, of course, and put in just enough food to satiate both strata.
When considering these strata, you’re probably only going to need to consider the fish, not the inverts. Snails just eat algae or scraps, so do the hermit crabs and others. They’re used to catch-as-catch-can, so you don’t really need to worry about them too much.