The sunfishes currently in quarantine are being held at about 17 C and are being fed in access with live brine shrimp nauplii. What is very interesting is the rate of growth (not quantified) that is very much better than promoted by feeding even our best formulated diet that the fish are eating. The formulated diet works great at the warmer conditions we used to define the production season.
Live Food Promoting Growth at Low Temperatures in Sunfish
Started by
Guest_centrarchid_*
, Apr 01 2014 09:20 AM
7 replies to this topic
#2
Guest_Nearctic_*
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Posted 03 April 2014 - 11:17 AM
I have seen with Dollar Sunfish that below 21C the growth rate ( on dry foods ) is very slow.
I am soon to have 4 new big tanks. I can try some brine shrimp experiments.
I am soon to have 4 new big tanks. I can try some brine shrimp experiments.
#3
Guest_Erica Lyons_*
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Posted 03 April 2014 - 11:37 AM
How big are the fish that are eating brine shrimp nauplii? I've found around 3 inches they stop being able to see and eat them.
#4
Guest_centrarchid_*
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Posted 04 April 2014 - 10:42 AM
These animals were 1" or less. Bluegill at 12" can fatten up on nauplii.
#5
Guest_gerald_*
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Posted 04 April 2014 - 11:13 AM
Gill raker length and spacing differences among species may be a factor in the size/age at which fish stop eating tiny prey. Bluegill are well-adapted for mid-water plankton feeding, so it's not surprising that big bluegill will still eat small plankton. Other sunfish that feed more on fish, snails, and larger insects as they grow (and have shorter or wider-spaced gill rakers) would probably give up on nauplii sooner (at smaller body size) than bluegill.
Erica -- what kinds of fish are you referring to that stopped eating baby BS after reaching 3 inches?
Erica -- what kinds of fish are you referring to that stopped eating baby BS after reaching 3 inches?
#6
Guest_centrarchid_*
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Posted 04 April 2014 - 11:24 AM
I do not think this is a particle size issue. I can get fish to each pellets just fine but at lower temperatures growth seems much slower when fed such.
#7
Guest_gerald_*
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Posted 04 April 2014 - 04:08 PM
A few wild speculations on your low temp observation: (i love wild speculation, if you haven't noticed) ...
1) live food may be better tasting and/or more interesting, and excites their feeding instinct at low temp when they're not so hungry.
2) the additional activity involved in pursuing live food may boost their appetite (granted, not much effort required for baby BS);
3) different foods may require different digestive enzymes, and enzymes needed for pelleted food might be less efficient or harder to make at low temperature, so the food stays in the gut longer.
1) live food may be better tasting and/or more interesting, and excites their feeding instinct at low temp when they're not so hungry.
2) the additional activity involved in pursuing live food may boost their appetite (granted, not much effort required for baby BS);
3) different foods may require different digestive enzymes, and enzymes needed for pelleted food might be less efficient or harder to make at low temperature, so the food stays in the gut longer.
#8
Guest_centrarchid_*
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Posted 04 April 2014 - 06:10 PM
3 is one I am leaning heavily on. Gut fill is realized on all. Owing to observed feeding methods the live food does not require much effort or time to consume.
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