Most effective aquatic scavenger?

krystian

Registered Member
Jul 26, 2005
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Hello,

I am researching aquatic scavenger species, and I'd like to post to this community forum to get some opinions and feedback.

I'm looking into which aquatic scavenger is most 'effective'. By "effective", I propose rating multiple dimensions to help us discuss this topic*:

  1. Diversity of Food Consumed
    - Ranking the diversity of a creature's diet. Is it just carnivorous? Is it just a herbivore? Omnivorous? Will it also consume or nip at things other aquatic life won't? (think: plastic plants, roots, small rocks, shell fragments, skeleton pieces, rotting carcases (how about of it's own kind- like cannibalistic scavenger?) How about algae?
  2. Appetite
    - Does this creature eat a lot of small feedings frequently, or large feedings infrequently? Does it have some innate advantage to prevent the ill effects of overeating?
  3. Waste Output
    - Does the scavenger's body quickly convert food to waste? Does it output lots of waste for what it eats or little waste? How effective is food absorption?
  4. Size/Consumption Ratio
    - Some scavengers get big, others stay small (pygmy). In an ideal size comparison with other aquatic life, will a small creature eat the same amount of food as a comparable larger creature?

Please propose any aquatic life which you feel may win as most "effective" scavenger. Also, please note if freshwater, salt water, or tolerant to both.

* This list is by no means complete. I'd love to add more dimensions, in hopes of helping develop better metrics to answer this question.
 
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I guess I'd suggest adding a few more layers. Compatibility is a big one--there are many excellent scavengers that won't work in community setups because of the risk they pose to the other inhabitants. second would be life stage--many animals are scavengers at some stage in their life, but may turn to herbivores or carnivores as they mature.

For some of your categories, it's going to be tough to get solid data--food absorbtion, for example, is tough to judge in a community setup, especially one that includes micro scavengers such as snails, since the fecal matter seldom remains intact for very long. A further complication is that most fish will continue to eat long after their stomach is full, resulting in undigested food being puched through rapidly--they would have digested it better if there was less food available.

I'd be interested in knowing what you want to do with info, as well.

Here are my candidate:

Common Crayfish. Omnivore, will eat anything it can catch, including live fish and other crustaceans. Will re-arrange tank decorations, and consume aquatic plants. Stays under 6 inches, and smaller species are available. As long as not overfed, fairly efficient scavenger with minimal waste. FW, some tolerance for low brackish conditions.

Snails: Omnivore to herbivore. Many species are harmless to healthy aquatic plants, but not all. Reproduces in proportion to available food supply, can reach pest levels in poorly maintained environments. Requires no special care. A number of different species are available, with everything from FW up to full marine found readily and useful for a variety of setups.
 
Out of all of my fish, the best "scavengers" are my Curviceps cichlids. Although not generally considered a scavenger fish, they have big appetites for their size and seem to feed constantly on leftover food, dead plant matter, and algae. They also love eating snails, and between them and my dwarf chain loaches I can't keep pond snails alive long enough to reproduce in the tank. As for size, they are at 3" and pretty much full grown.

The dwarf chain loaches are excellent scavengers as well. They don't seem to touch algae or plant matter, but they are always in a frenzy searching for leftover bits of food.Their appetites seem endless. They also love to eat small pond snails. As far as size goes, mine are at 2" right now but have some growing to do.

Not as scientific of an answer as you were hoping for perhaps, but I have no way to measure things such as size/consumption ratio.
 
OrionGirl said:
I'd be interested in knowing what you want to do with info, as well.

I'm just trying to find this out for myself (no research paper or anything like that). I'd like to know if there is an aquatic species that evolved to overeat in order to survice poor nutrient habitats, seasonal hardships, or otherwise difficult access to frequent food.

Someone the other day I think suggested that Corydora are very effective at devouring everything on the floor bed. How's that run by you guys and gals?
 
Nice to have scavengers, but easier to just not over feed. Most scavengers in tanks starve because not enough food is left/fed to them. This may take months to do because they do get some food.
 
hands down, my vote goes to commn ramshorn snails. there are many great scavengers out there though, but I have yet to have anything help my tanks as much as the ramshorns do.
Dave
 
I find little cory catfish to be pretty good at cleaning up leftovers for a small little fish. They keep the gravel in my tanks pretty clean and tidy actually....but, they're really the only scavanger I've had any experience with.

In fact...I went away on vacation and when I got back....I was missing a panda cory....no trace of it anywhere !! and I have a glass lid on the tank which makes it impossible for him to have jumped out....did a full cleaning on the tank and still no cory....apparently he died (was a new fish I had just bought)..and his brothers ate him right down to nothing !
 
My Amano shrimp are constantly eating either algae off decorations or food if they can get to it before everyone else.
 
Cories tend to be mediocre scavengers, in my opinion. They will consume a variety of foods, but they really aren't that voracious a feeder, about in line with most tropical fish--if food is there, they'll eat, but they won't start targetting non-food items. Some of the larger cats will--but mostly those that get too large for home aquaria. Red tailed cats come to mind--I know Mojo had his eat a large rock. Mo got the rock back by feeding the cat enough that it vomited, a fairly common reaction in fish that will eat just about anything.

Actually, most animals that live in low-nutrient environments are better served by having slow metabolisms, large fatty reserves, or being able to go dormant. The problem seen in cold-blooded animals that binge (or are overfed) is that they have such slow digestive processes that if the food were to remain within their systems long enough to be digested, it would begin to rot, causing gas bubbles in the intestines and typically death. So, the just pass the food out undigested, giving them little benefit.
 
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