Effects of feeding too much on tank water quality

[skjl47]

frequent pooping...

more food = more water changes

I noticed the more food = more poop.

ive tried feeding one week of pellet only and seems like the water is more cloudy than when i feed tilapia or smelt for a week.

some fish seem to process the same pellets differently through their bodies, affecting what may go in the water column. My O will have big piles of poop but its soft and easy to break unless I scoop it up carefully. The blood parrot and severum tend to have firmer stuff thats much easier to sweep and clean

The thing I notice with fish, is because in nature food is not always abundant, fish don't have a shut off valve telling them to stop eating. They will continuously eat until the source is gone, and in nature this serves them well.
In captivity however, this instinct doesn't go away, so if excess food is presented, fish will eat constantly whether it is good for them or not.
And in the same mode, even vegetarian species when confronted with a protein source (whether a glut of only protein is good for them or not) will gorge on it. I'm not saying the protein itself is bad, but in nature the fishes digestive system has evolved to balance it out with algae, detritus, and leaf litter that help work that protein efficiently thru the tract.

Predatores like Parachromis, or Petenia seldom catch meals every day, so have evolved to live under those conditions where only eat every 2 or 3 days.

So power feeding is often not a good idea, and if you do power feed to get that oscar, dovii or jag big fast, should realize with each growth spurt it will need more water changes, and soon a much larger tank.

With the fish I have very little goes uneaten unless I try some type of food they don't like. But the ammonia level does go up after feeding (from 0 to about .005) for a few hours.

Hello; Had some time to kill this morning so went back thru this thread I started a while back. It has been dead for a while so I figured most everyone is finished with comments. As I read thru it I picked passages of interest as quotes to include in this summary of the thread so far. The thread went off on some interesting side tracts which is fine and normal for threads but I left out the side issues for this summary. Not because of lack of merit but because I had asked a specific question at the start.

Of the statements more on topic I gleaned a few things. One which is very logical being that more food eaten equals more poo. Another is more poo equals more WC which is also very logical.

Two things stood out to me as interesting observations. One being that different fish seem in terms of the poo they make to process the same food source differently. After some thought I can see the logic of this.
In my studies I learned there are three general types of digestive tracts, carnivore, herbivore and omnivore. Each type tailored to a particular sort of diet and lifestyle with us humans being the omnivores and an example of a generalist sort of feeder.
The second that stood out to me is very similar but sort of looking at the other side of the coin. The example was about feeding the same fish different sorts of foods. That being pellets compared to tilapia or smelt with the outcome being they process the foods differently.

The observation that fish do not have a shut off valve which tells them to stop eating is one I have long know of. Brought to mind back a few decades when I would collect wild foods. I had found a small pond loaded with tiny tadpoles which I collected. I started feeding them to a tank. One fish gorged and then threw up. Then the fish started gorging again. I did some checking and decided to not use local amphibians any more as some can have varying levels of toxins in their skins.
I guess this sort of observation over decades is what led to my initial question. I know fish will eat too much. I know they will eat many times a day if we will feed them. They can be fat pigs that just ate 30 minutes ago and will beg for food every time I approach my tank.

My general notion to my own question includes at least two parts. One being I figure it is better to have food pass thru a gut than to decay in the closed system of a tank. That gut can be in a fish or in a snail as I almost always keep snails in my tanks. I suspect fish or snail poo may promote a more suitable population of bacteria and other small critters than uneaten food which rots in the water or filter.
The other part is even if every bit of food is swallowed that too much has a negative effect on water quality and leads to some suspicion such over stuffing is not what the fish evolved to deal with as an ongoing thing.

I now ponder the notion of stocking a tank based on digestive system types. Would such a stocking make food selections simpler?

Anyway thanks to all who commented and even the tangents were interesting reads. Also the inevitable spats were not too heated. So many of us have ongoing grudge buddies on this site so the spats are a common fixture.

 

[duanes]

I now ponder the notion of stocking a tank based on digestive system types. Would such a stocking make food selections simpler?

[/QUOTE]
This brings up an interesting dilemma, in the confines of aquariums.
In nature, habitats support, carnivores, vegetarians, and omnivores because each trophic user is needed to keep the system working in balance.
Most tanks however (unless the species are small, or the tanks massive) cannot handle that kind of specialization.
I have kept many different vegetarian cichlids, but keeping different vegetarian species together often results in each species seeing the other as competition, and promoting aggression, or worse (IMO) hybridization.
When keeping Tropheus, it is recommened that a large group of 1 species to a tank is best, either because of aggressive competition to hold stress to a minimum.
I have found the same to be true with fruit eaters like Vieja, plant eaters like Cincelichthys, and Etroplus, if the tank is under 300 gallons, young adults of different species will instinctually kill each other over agri-turf.
Yet if carnivores and strict vegetarians are kept together, and trophic competition is not perceived, some individuals end up bloated and blocked from eating a food they are not evolved to eat, unless a varied diet is provided.
Commercial prepared foods make life easier these days, but if, for example Tilapia fillets are regularly fed to satisfy Parachromis, but become a regular diet for Vieja in the same tank, the Vieja may end up with digestive issues.

 

[RD.]

If one picks their food wisely, there is seldom an issue in feeding carnivores, omnivores and herbivores, all in the same tank, all eating the same food. I have done this in countless set ups, with countless species of fish. As Duane stated, commercially prepared pellets make life pretty easy for most. If the fish won't eat pellets, and one has to target feed certain fish with meat, then also as Duane suggested the potential for digestive stress (bloat etc) is much greater. This is really no different than one designing any community tank, there needs to be a plan in place before one starts - or the fish suffer down the road. Behaviors have to mesh, just as feeding strategies, or a gluttonous school of top-mid water feeders could leave the bottom feeders with nothing more than scraps.