Blotched minnow ?

Whinging pom

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Every so often in kick samples down the brook we get minnows with these black blotches under the skin . Tried googling but keep getting aquarium problems .
Not
33F8003F-CA44-45DD-B85E-D595C3787BF8.jpeg
that we can do anything about it but it would be good to know what causes it …any ideas out there?
 

Rhithrogena

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Every so often in kick samples down the brook we get minnows with these black blotches under the skin . Tried googling but keep getting aquarium problems .
NotView attachment 43548 that we can do anything about it but it would be good to know what causes it …any ideas out there?
I realise you probably will not know, but are they like it before they are sampled?
Stress can cause strange melanistic responses in fish.
Kick sampling could easily 'bruise' them too.
 

Whinging pom

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Interesting …
No idea if like that before sample. Looking down on shoals of minnows I never see it.

Some blotches like on the flank above looks deep within the flesh like a parasite in there . The one on the head is the more typical form and can appear anywhere on the body almost like a mole ( which I guess would be melanistic ?! )
in the 12 years of kick sampling down there we’ve only noticed this recently
 

Rhithrogena

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No idea if like that before sample. Looking down on shoals of minnows I never see it.
That might be telling!
Some blotches like on the flank above looks deep within the flesh like a parasite in there
Only a necropsy could confirm this, but many freshwater fish have multiple species of endoparasite inside them, as well as obvious exoparasites on their skin.
 

aenoon

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Every so often in kick samples down the brook we get minnows with these black blotches under the skin . Tried googling but keep getting aquarium problems .
NotView attachment 43548 that we can do anything about it but it would be good to know what causes it …any ideas out there?
Are the minnows that show those marks all male?
If so any red marks below lateral line?
Is them changing colour prior to spawning, males will go very black with red below lateral line.


Shows what I am suggesting.
 

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