Overfeeding Stingrays?? Lead to problems down the road??

[T1KARMANN]

some good points hear my temp is 86 all the time but at water change it drops to 78 its only at 78 for 3hrs

i do more than enought water changes with 25% water changed every 3-4 days i chould get away with 25% every week

this method worked very well last time so i will stick with it

 

[Big Daves Rays]

I only feed my rays once a day, and every few days I skip a day. The rays are breeding and they seem healthy. I also give them a varied diet. Smaller rays and pups get more food obviously.

 

[keepinfish]

Not enough is easy to say, if the rays lose weight they have parasites or not enough food.

Juvenile rays need more food than older ones that is allright.
Juvenile rays feed in the wild mainly on insect larvea or Isopods and other small things. All studies untill now show, that some species (the smaller rays) are insectivore the entire live, while other species start feeding on fish, shrimp and snails when they grow larger than 12".

Feeding young rays alot insect larvea is ok. I feed pups three times a day insect larvea untill they have a nice belly.

If you use other food with higher caloric content you need to calculate how much of this food is equivalent to the caloric content of feeding three times a day insect larvea.

It depends on the kind of food, mainly the protein and fat content, but a rough guess is to feed half the amount of fisch and shrimps and 1/5 of the amount when you feed pellets (my pellets have 50% protein and 10% fat).

For example, your rays can eat 100g bloodworms untill they full, the same caloric content is in 50g fish and 20g pellets.

The rays can eat 100g fish or 100g pellets too, but then they are overfeed.

I feed my two Itaituba rays (13.5" and 12.5") 50-60g fish/shrimps/mussels or 20g pellets per day and one day per week they get no food. Water temperature is 27-28°C (80.6-82.4F). With higher temperature you can feed more, lower temperature less.

Food content the rays cannot use for growing they store in the liver (mainly fat) or waste your water (faeces, ammonia through the gills). So you have to pay twice for to much food. You pay for the food and for water change to bring the excess nutriation out of your tank.

And overfed rays are more sensitive if they are stressed.
Even the stress of mating can lead to death, that happened once here in Germany, a male and female ray died during mating.

And in the actual case discussed in the german board possibly the ray was fat and stressed because of a missfunction of the filtration system. We will see what the vet find out.

that is quite a bit, 60 pellets a day is around 20g, is a lot of food...imo

my rays are both about 10" and 25-30 a day is all they get, and they look pretty fat. 3 or so times a week i put in about 25 pcs of medium sized shrimp in also though.

 

[Brent]

i can be feeding enought then as mine want food everyday

brent your rays are adults so they may not need as much food to grow

i normaly cut the food down to 1 feed per day when they get to 12inch +

true

 

[Miles]

Rays in the wild eat primarily a diet of crustaceans and insect larvae, especially when young.. even when old, they eat fish and crustaceans.

These crustaceans, insect larvaes, and other organisms are all 'gut-loaded', per say, in the wild. This makes the food source of stingrays in the wild to be very nutritionally advanced, varied, and likely un-recreatable.. These food sources in the wild consume algaes, vegetation, insects, and a plethora of other things to provide a wide variety of vitamins and nutrients. The more freshly consumed the matter contained within the food source, the more that nutrition that food source passes onto the rays.

The bloodworms, market prawns, and other seafoods we offer them, do not offer this varied nutrition, nor any gut-loading nutrition at all for that matter. The seafood we offer in captivity is ALOT less varied in nutrition, but very high (probably too high) in Protein, Carbs, and Calories.. The more processed the seafoods, the less nutritionally advanced it is.

So, in order for a Stingray to compensate for the lack of varied nutrition, they must over-eat in order to fulfill the wide range of vitamin requirements their body needs to osmoregulate, develop, and grow..

Ever heard of Coprophagia? When you're dog eats it's own poop? It's caused from a lack of nutrition in their body, and their bodys natural compensation instinct is to re-process the food in order to extract the nutrition needed. Many small animals, especially Rats, practice coprophagia even when they are not nutritionally depraved.

So, relating that to Stingrays.. I believe Stingrays "gorge" themselves on high protein seafoods, that are less nutritionally varied, in order to compensate for the lack of varied vitamin sources in that food.

It's kind of like the toys in the boxes of cereals.. If all you wanted was 10 toys, you would have to eat 10 boxes of cereal to get your 10 toys.

So if a ray wants some Vitamin K, he only has to eat 10 market prawns to get his Vitamin K.. when in the wild, a single small organism could fulfill the need for Vitamin K.


This is my theory.

I hope it makes sense.


PS.
I agree with overfeeding as a possibility.. Natural fasting and day-off scheduling is a good idea.

A healthy ray in the wild is never 'overweight', probably because it gets enough nutrition without having to eat excessive amounts of fatty seafoods.

I believe rays eat the way we do because hobbyists sacrifice nutritional variety for pallatable foods.. Pellets, Insect Larvae, and Worms are likely better staple diets than seafoods.

I agree that metabolism in captivity is differing from metabolism in the wild, meaning we should watch what we feed very closely..

 

[Miles]

Bump for intelligent conversation

 

[T1KARMANN]

in the past the only foods i would feed my rays were prawn and frozen blood worm

then 3yrs ago i throw in some pellets and the rays loved them

i think pellets are a great food for rays my rays have never been happyer since on the pellets food

complete foods are good for dogs so they must be good for the rays

 

[rayman]

that is quite a bit, 60 pellets a day is around 20g, is a lot of food...imo

my rays are both about 10" and 25-30 a day is all they get, and they look pretty fat. 3 or so times a week i put in about 25 pcs of medium sized shrimp in also though.

Your rays with 10" have half the weight of mine, so the amount of food calculated as % of body weight is almost the same. I did a more accurat measuring of the pellet food amount and it is 16-18g Pellets. They get the pellets three days a week, the other days frozen food.

 

[rayman]

These crustaceans, insect larvaes, and other organisms are all 'gut-loaded', per say, in the wild. This makes the food source of stingrays in the wild to be very nutritionally advanced, varied, and likely un-recreatable.. These food sources in the wild consume algaes, vegetation, insects, and a plethora of other things to provide a wide variety of vitamins and nutrients. The more freshly consumed the matter contained within the food source, the more that nutrition that food source passes onto the rays.

This is the reason why I prefer food items that are complete like krill, small shrimps, small mussels, small fish. So the rays eat the whole animal with all the content you mention here.
For shure best would be live food, but there is the risk of parasites.
Frozen food should stored max. 6 months because of vitamin loss.
High quality pellet food has vitamin suplements, but very high protein content. So it is very important to control the amount of this food. To feed the rays pellets until they full is to much protein.

 

[African_Fever]

Very good thread.

The biggest problem I have with many people's way of thinking is knowing what the rays are doing in the wild - how do you know the rays aren't constantly looking for food, eating whenever they can because they are limited by their food source? Are there any papers or studies on this, that is the amount of time spent hunting every day? How many people here have been in direct contact with exporters asking them exactly how the rays look when they're caught, if they're showing hips very often, or if they ever come across very fat rays with their 'booty' after a large meal? It just seems that everyone talks about what the rays are doing in the wild without actually knowing or basing their knowledge on anything factual. Everyone seems to ASSUME that rays can eat as much as they want all day, every day, because the food 'is just there'. Bioligically, this doesn't make any sense; food is a limiting factor to aquatic populations as it is to all other populations. Other apex predators have been shown to kill just for fun (there've been studies on great white sharks killing seals for fun), so why is not possible that stingrays sometimes attempt to kill their tankmates, even when they're full, because it's instinctive?

I agree with Andreas in that pellets are much more nutritionally dense than 'natural' food sources, and therefore feeding pellets until completely full is too much protein, and could very well lead to issues down the road.

JM2C