Electric blue jack dempsey

Toby_H

Polypterus
MFK Member
Jun 21, 2007
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I bred them for years. My pic is a mated pair I had.

They are, on average, less aggressive, slower growing and top out a bit smaller than standard Dempsey's. Though you will see an occasional ideal specimen that can match size and aggression of a standard.

As mentioned, they are also prone to parasitic infections. I found it to be most true when small. Once adults, mine seemed to get passed that. I often used UV lights and when doing so I found my juvenal survival rates went up considerably.

My suggestion is, if you want a quality Blue Dempsey as a feature to your aquarium, buy a group of them, grow them out and keep the nicest one (or pair). Then rehome any other survivors. Though that is my approach with nearly any show piece fish I get. The more important the show piece, the larger the group I start with.

Since I mentioned pairing Blue Dempsey's, it's important to add that a Blue/Blue pair will not produce offspring that will live much past the free swimming stage. I've had at least two females that were able to pair off and breed. Each of them were paired off with multiple Blue males, never did a brood make it more than 2 weeks into free-swimming. That said, both females produced healthy broods with non-Blue males. Many others have reported similar results.
 

Theos.dad

Jack Dempsey
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Jul 30, 2021
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Hey there Toby, you mentioned them being slower growing. I've definitely noticed this with the pair I have. Did you ever have any fish that absolutely didn't grow at all past 2 inches? Of the pair I've had for 4 months, one has made it to 3.5 inches and looks great and the other has been at 1.75" since I got it. In the last month it has somehow come up with popeye in a clean healthy tank that's been cycles for a couple years. I'm curious if he's going to grow at all tbh. I've had a lot of fish and have never seen a cichlid not grow at all over a 4 month period (not from at a juvenile age anyways) he eats normal, very food aggressive. Interacts with others. Just a really small guy for a while now.
 
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Toby_H

Polypterus
MFK Member
Jun 21, 2007
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Females grow slower than males. Which is common but stands out more in a slow growing morph.

If a fish has a problem, such as developing Popeye, their system will spend energy on healing rather than growing.

Yes I've seen individual that didn't grow, and its usually bad news. Sorry.

I would suggest isolating the non-grower to treat the eye and/or parasites.

Also, if the small one turns out to be female, she'll do better if kept away from the male until she grows up a bit more. When a young female's system puts energy into reproduction, thats energy not going into her own development. Again, thats usually not too big of a deal, but until we are dealing with a fish already compromised.
 

Theos.dad

Jack Dempsey
MFK Member
Jul 30, 2021
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Females grow slower than males. Which is common but stands out more in a slow growing morph.

If a fish has a problem, such as developing Popeye, their system will spend energy on healing rather than growing.

Yes I've seen individual that didn't grow, and its usually bad news. Sorry.

I would suggest isolating the non-grower to treat the eye and/or parasites.

Also, if the small one turns out to be female, she'll do better if kept away from the male until she grows up a bit more. When a young female's system puts energy into reproduction, thats energy not going into her own development. Again, thats usually not too big of a deal, but until we are dealing with a fish already compromised.
For the past month roughly I've had the smaller of the 2 in a community tank of tetra and smaller fish. The larger of the two is actually female I believe. The smaller one pretty much roams around the bottom of the community tank oblivious to the rest of the world so I'm not sure how great his vision is. As far as treating the popeye I've done one course of erythromycin (medicating the food) and now i've been doing Epsom salt baths to try to cure it, but in the past I've never been able to cure popeye that wasn't from the fish taking a hit of some sort. I've spent a lot of money trying on more than a few fish and never once have had the popeye go away unless it was from the fish scratching their eye or taking driftwood to the eye etc. ( which is why I don't use driftwood in tanks with big fish anymore) have you ever had luck treating popeye that was being caused by kidney related fluid retention? I don't have much faith in the little guy making it very long tbh. It's just odd to see a fish seem so healthy yet not show any signs of the nourishment I see him getting.

Also with the popeye. It's still at the stage of just being the clear part of its eye that's swollen. The actual white or colored part of the the is in place and has been through the entire ordeal.
 

Tj203

Piranha
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Sep 11, 2019
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I had one in my tank and it just did not grow that fast and then it died. It was one of the few fish I have ever lost in that tank. I would never buy one again they are definitely weaker. I did not believe anyone because my tank was so big that's why I bought it and I regret doing it. I have never seen an adult one in a pet store And they are expensive too
 

Theos.dad

Jack Dempsey
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Jul 30, 2021
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I agree they are weaker. I'm pretty confident the larger of the two will make it to a good size at least before it croaks. My best friend has one around a year and s half old thats close to 7.5 inches( is the fish that made my wife want one) and it's had several ups and downs to make it that far but its all around healthy ATM last I heard. Maybe I'll get lucky with one.
 

Jexnell

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Jul 17, 2017
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I bought one from The Wet Spot in Portland, Or.
20170608_094914.jpg
He quickly paired up with a normal female JD20170727_161724.jpg
I kept them about six months. 20171203_171913.jpg20171203_172112.jpg
At about the 4.5 inch size I gave him to a fellow MFKer. He was added him to his Platinum breeding project. Last I heard he was ten inches long and four years old or so.
2F0E84C2-11E3-40B0-872C-1B31A8A9C4DF.jpeg.jpg14EC33E4-177B-4996-9E81-5F17A6041330.jpeg.jpgD46A31AC-70FF-4733-9B84-8130E0535F58.jpeg.jpg

So even a known weak breed, if well cared for can have a wonderful life.
 
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