Fish Keeping Myths- Overfeeding

[Biotope Biologist]

This topic has been brought up from time to time, but in my other social medias the topic of overfeeding fish has come up again. It goes something like this:

 

"Fish lack the braincells to tell them when to stop eating so you can kill your fish by giving them too much food, because they do not know when to stop..."

 

I am not sure why this topic grinds my gears more than others, maybe it's the constant attempt to explain it with false science. I am here to tell you that fish do in fact have many external and internal inputs that control their hunger and whether or not they are satiated or are overeating. This is a very well researched topic and is very important in aquaculture as they try to min/max their food to health ratio for commercially available foods. I won't go into gruesome detail on this topic as it can get quite, science-y, but I will leave a recently published article that attempts to digest some of it's references. Of which there are 140:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8715717/

 

In my personal experience, temperature seems to be one of the most important for digestion rates in fish. Especially goldfish, who can inhabit a very large range of temperatures from 50-85 degrees Fahrenheit and are constant grazers. I am keeping this very succinct as to not launch into a full blown 5 page rant, and so that others may share their pet peeve myth or maybe ones they have heard that they want explained further. Or share your experiences with this myth and how it impacted you in this hobby.

[Lennie]

In terms of science perspective, I am not qualified to say anything. I don't have a career related to science. 

 

In my experience, some fish do be weird. I had a female rummynose, I think she had legit no understanding of being full. She was eating in a level she loses her color, goes pale and gasping with a HUGE belly. Every single time. Having struggle swimming. She was going for her own food, bottom dweller food, snail food, Every food in the tank. Nonstop. Other than eating times, she is all fine, healthy and nice.

I have a female betta in my betta sorority that is the same. Every other fish are normal, however, this gold girl would eat in a level she explodes if given a chance.

As I have had tens or even hundreds of fish until now, I had a chance to make some observations myself. It is hard to generalize, but for some reason, there are some fish like these that I am not sure what drives them into this eating behavior. Maybe survival instinct?

 

That being said, I feed my fish tanks, when I'm done, the first tank legit acts like they haven't eaten in ages again. I'm not sure how what I think about fish knowing that they are full in this regard.

 

Like yes, If I dump in a whole package of food, there will be a ton laying down uneaten spoiling the water. But pretty sure, most fish I have would also eat in a level they are in an uncomfartable position before they stop. Even then, I bet they would eat and spit, keep playing with food 😄 

[xXInkedPhoenixX]

I think mine is "every tank needs a heater". Other than tanks where I keep Betta fish who I DO believe need to be in at least 78 degree waters (mine are in 80 degrees minimum) I don't run heaters in my tanks. It never made logical sense to me that most fish we keep would need consistent temps and IME seems more detrimental to get fish to be reliant on it. Natural daily fluctuations in water temps is exactly that, natural. I keep my home warm enough my tanks are 73-77 on a daily basis. IMO heaters are optional depending on fish and a fish keepers' individual situation. I was made to feel guilty for "killing" my first batch of Otocinclus- the LFS told me my fish died because the water was too cold. I have proven that this bit of "advice" was bunk - my later batches have made babies in the same tank that "killed" the first batch - there was, and is still not, a heater in it. A video Cory made I later ran across validated my experience and I am forever grateful for his honest advice. 

Edited June 22, 2023 by xXInkedPhoenixX

[DaniV]

Some fish are just greedier than others, it seems.  I'll feed by betta a few pellets for him to eat, and then sprinkle some mini pellets for his neon tetra roomies, and despite eating his pellets he will go and nom away on the tetra's food.  My mollies and swordtails will eat just about anything in front of them, even if it's the blanched zucchini for my bottom dwellers, all the while my harlequin rasboras are content with just grabbing what they want and going along their merry way.  I've been keeping the temps on my tanks around 78, dunno if that helps.

[anewbie]

I didn't read the article but fishes can over-eat in the sense that they get 'fat'. I'm not a betta person but i've seen several cichild get quite fat over time and like humans this isn't esp good long term. So in that sense they can over eat....

[Biotope Biologist]

2 hours ago, anewbie said:

I didn't read the article but fishes can over-eat in the sense that they get 'fat'. I'm not a betta person but i've seen several cichild get quite fat over time and like humans this isn't esp good long term. So in that sense they can over eat....

Yes you bring up a good point that I should clarify. Fish can over eat. Any animal can over eat. Truth be told we don’t fully understand the science behind why humans and animals over eat. Whether it’s stress, poor quality foods, or some combination of several factors.
 

What is wrong is that A. They don’t possess mechanisms to stop themselves and B. Overeating leads to death. Neither of those assertions are true. 

[Guppysnail]

I always thought that myth was humorous. If fish did not know when to stop eating there would never be leftover uneaten food in tanks. 
I do have a completely non-scientific theory on fish that overeat to obesity.

I usually get my breeding groups from 2-3 sources in hopes of the best genetics prevailing through natural selection. I will on occasion receive fish that were underfed chronically and then fasted to ship that did not have body stores to weather the fasting very well. Those that survive that ordeal will usually end up obese while the others in the tank from a different source that did not go through the near starvation event will remain appropriate weight. So potential fear of going through another starvation event or food becoming scarce again. 🤷‍♀️

The myth that gets me is fish don’t feel. I’ve always un-scientifically thought if a thing can feel fear it can feel more than we probably give it credit for. 
I’ve watched mated fish lose a mate and exhibit stress to the point of refusing food. 
My most recent example is my honey gourami. I had a group of 5 boys 1 girl. I split a pair to the tank next to it in hopes of babies. Both groups stayed at the glass closest to the other tank looking at each other. Both groups refused food. I put the group back together and each fish immediately interacted with each of the other fish. It looked like reaffirming social bonds. Then each fish returned to the spot in the original tank they claimed as theirs and the girl came front and center the way she does at feeding time.  
My thought is the way fish feel may be different than the way we feel but they do feel. 
I am PRO-anthropomorphize. 🤗🤣
 

 

 

[Jackson]

15 hours ago, Lennie said:

I have a female betta in my betta sorority that is the same. Every other fish are normal, however, this gold girl would eat in a level she explodes if given a chance.

 

My female betta is the same way . Girl can consume food ....

 

[Chick-In-Of-TheSea]

18 hours ago, Lennie said:

rummynose, I think she had legit no understanding of being full.

Can we plz name this fish Galactus?

[Chick-In-Of-TheSea]

Mystery snails eat a lot, then they all go to the top and have a food coma nap while raining poop down. lmao

I think @Guppysnail calls this behavior "reading the newspaper" 

[Tanked]

I think feeding is a perfect breeding ground for myths because there is no uniformity in the process under normal conditions.  How big is a "pinch".  My barbs will consume everything they can in about 2 minutes.  Minutes later they will begin grazing through the substrate like sheep in a field.  The community tank is smaller but gets more food. The SAEs get there first, followed by the larger tetras.  There has to be enough to insure that fish that won't feed off the surface get some.  I feed once a day, and still wonder if I'm overfeeding.

 

 

[Lennie]

1 hour ago, Chick-In-Of-TheSea said:

Can we plz name this fish Galactus?

Here she is

[Jackson]

Have my female betta so she bites my finger, then I release the food . It's funny she just jumps at the finger and bites it .

[Guppysnail]

37 minutes ago, Lennie said:

Here she is

Maybe Gladys is preggo?  🤣 At leadt you know she eats good 🤗

[Biotope Biologist]

8 minutes ago, Lennie said:

Here she is

Thats a chonk if I’ve ever seen one but her color’s definitely show that she is quite happy!

 

4 hours ago, Guppysnail said:

The myth that gets me is fish don’t feel.

So I am a nerd… and I enjoy reading new to science books that for reasons may be hard to publish in journals. I read a book that I can’t recommend because it was so boring. But it was called “incomplete nature: how mind emerged from matter” by Terrence W. Deacon.

 

It basically shows how we have very little understanding of intelligence and how we can’t even fathom how it could have evolved. Let alone multiple times in multiple ways. Swarm intelligence in the case of ants and termites to displaced intelligence in octopi and cuttlefish. We are learning that every living thing is constantly learning from its environment and changing.
 

Oh and one more thing I have learned from my readings. Don’t read any books published by primatologists. They want so badly to attribute human traits to bonobos and chimps. We are nothing like them. They have an incredibly different social heirarchy. The closest any scientist has found to human-like communities is actually a monogamous parakeet that inhabits South American plains. They lie, cheat, and steal. But they also show remarkable compassion. Will raise chicks that are not their own. And hatch ridiculous schemes to piss off hawks and other predators.

 

Anyway I have derailed this topic to the point where I may have killed it carry on my fellow nerms! 😋

[Guppysnail]

2 minutes ago, Biotope Biologist said:

Will raise chicks that are not their own. And hatch ridiculous schemes to piss off hawks and other predators.

I would laugh myself silly watching this. Thank you for the awesome information 🤗

[Lennie]

7 minutes ago, Biotope Biologist said:

Thats a chonk if I’ve ever seen one but her color’s definitely show that she is quite happy!

 

So I am a nerd… and I enjoy reading new to science books that for reasons may be hard to publish in journals. I read a book that I can’t recommend because it was so boring. But it was called “incomplete nature: how mind emerged from matter” by Terrence W. Deacon.

 

It basically shows how we have very little understanding of intelligence and how we can’t even fathom how it could have evolved. Let alone multiple times in multiple ways. Swarm intelligence in the case of ants and termites to displaced intelligence in octopi and cuttlefish. We are learning that every living thing is constantly learning from its environment and changing.
 

Oh and one more thing I have learned from my readings. Don’t read any books published by primatologists. They want so badly to attribute human traits to bonobos and chimps. We are nothing like them. They have an incredibly different social heirarchy. The closest any scientist has found to human-like communities is actually a monogamous parakeet that inhabits South American plains. They lie, cheat, and steal. But they also show remarkable compassion. Will raise chicks that are not their own. And hatch ridiculous schemes to piss off hawks and other predators.

 

Anyway I have derailed this topic to the point where I may have killed it carry on my fellow nerms! 😋

 

she gets pale after meal time to be fair 

this is how her friends look like. You can see her behind

@Guppysnail

[JettsPapa]

19 hours ago, xXInkedPhoenixX said:

I think mine is "every tank needs a heater". Other than tanks where I keep Betta fish who I DO believe need to be in at least 78 degree waters (mine are in 80 degrees minimum) I don't run heaters in my tanks. It never made logical sense to me that most fish we keep would need consistent temps and IME seems more detrimental to get fish to be reliant on it. Natural daily fluctuations in water temps is exactly that, natural. I keep my home warm enough my tanks are 73-77 on a daily basis. IMO heaters are optional depending on fish and a fish keepers' individual situation. I was made to feel guilty for "killing" my first batch of Otocinclus- the LFS told me my fish died because the water was too cold. I have proven that this bit of "advice" was bunk - my later batches have made babies in the same tank that "killed" the first batch - there was, and is still not, a heater in it. A video Cory made I later ran across validated my experience and I am forever grateful for his honest advice. 

I agree with this one; mostly.  I have heaters in my community tanks, since in winter my thermostat is set to 68° during the day and 60° at night.  The guppy and shrimp tanks don't have heaters.

[xXInkedPhoenixX]

@JettsPapa well no, I think you are saying you agree with me entirely not mostly  - because "every tank needs a heater" is not true, and it's dependent on your situation. If your house doesn't sustain acceptable temps to keep tanks warm then yes a heater is necessary, but if that same tank you mentioned was a goldfish tank you'd be fine without one. I actually zone heat in the winter- the room is kept at a warm temp so I don't need to heat the tanks- if I didn't do that, I'd have to put a heater in the winter. 

I'm just railing against heaters being sold as "absolutely necessary" equipment when starting a tank, everything has to be taken into consideration. 

Edited June 23, 2023 by xXInkedPhoenixX

[Chick-In-Of-TheSea]

2 hours ago, Chick-In-Of-TheSea said:

Mystery snails eat a lot, then they all go to the top and have a food coma nap while raining poop down. lmao

I think @Guppysnail calls this behavior "reading the newspaper" 

 

[anewbie]

I'm lost are we talking about fat fishes or tv shows ?

[Odd Duck]

On 6/23/2023 at 2:16 PM, anewbie said:

I'm lost are we talking about fat fishes or tv shows ?

Yes.  😂 🤣  

It seems the thread has taken on its own stream of consciousness.  Sometimes the hivemind drives the thread.  [See what I did there? Bzzzz.]

@Biotope Biologist, it’s funny, but I’ve either never heard that drivel of “a fish has no triggers to stop eating” or I just ignored that nonsense so well I had forgotten it.  It’s true that fish will overeat but not to the point of sudden death.  It can eventually catch up to them with disease secondary to obesity, but no such thing as acute death from eating appropriate, non-toxic, digestible food.  Moldy or otherwise toxic food (don’t eat pufferfish, kids) or foreign bodies (including spiky tank mates in this category) being a potential exception.

I hadn’t even considered that people might have thought about overfeeding in any way other than rotting food or excess fish poop polluting the water for causing acute death.  Chronic overeating is a different story.

Edited June 25, 2023 by Odd Duck
Clarify

[anewbie]

On 6/25/2023 at 2:30 PM, Odd Duck said:

Yes.  😂 🤣  

It seems the thread has taken on its own stream of consciousness.  Sometimes the hivemind drives the thread.  [See what I did there? Bzzzz.]

@Biotope Biologist, it’s funny, but I’ve either never heard that drivel of “a fish has no triggers to stop eating” or I just ignored that nonsense so well I had forgotten it.  It’s true that fish will overeat but not to the point of sudden death.  It can eventually catch up to them with disease secondary to obesity, but no such thing as acute death from eating appropriate, non-toxic, digestible food.  Moldy or otherwise toxic food (don’t eat pufferfish, kids) or foreign bodies (including spiky tank mates in this category) being a potential exception.

I hadn’t even considered that people might have thought about overfeeding in any way other than rotting food or excess fish poop polluting the water for causing acute death.  Chronic overeating is a different story.

Just remember no matter how hungry or well fed you are eating live catfishes is dangerous to your health as many fishes have learned the hard way; and for many the last lesson on what to eat....

[Odd Duck]

I once saved a large goldfish that decided to eat his cory tank mate. By the time the owners found me and brought it in, the cory had passed. So I only had to clip fins and extract it from his mouth.  Goldie did fine afterwards. 

[TheBlueBeetle]

On 6/23/2023 at 10:19 AM, Lennie said:

Here she is

You're gonna need a bigger boat.