# White Cloud Mountain minnow cardinals vs. golden White Cloud Mountain minnows



## ppaskova (Apr 27, 2010)

HI guys

I had for a while White Cloud Mountain minnow cardinals (7 of them) about 5-6 months ago I added 6 golden White Cloud Mountain minnows, which are little bigger than White Cloud Mountain minnow cardinals. For a while everything was fine and they both wore very playful with each other. But recently I noticed that only 3-4 White Cloud Mountain minnow cardinals left and they are hiding in plants all the time, but golden White Cloud Mountain minnows are very active and playful. They looked even somewhat aggressive to each other as well. But I noticed that they don't attack of chase other fish, including guppy fries. In addition iI noticed that my population of neons decreased as well (specialty the ones that was smaller than White Cloud Mountain minnows). Could it be possible that golden White Cloud Mountain minnows are harassing White Cloud Mountain minnow cardinals and small neons (as my other fish is bigger than them with exception of guppy fries) ? I have red that White Cloud Mountain minnows very peaceful and playful hardy fish but maybe golden White Cloud Mountain minnows not exactly that type ?


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## Fishfur (Mar 4, 2012)

Anything is possible.. not every fish behaves as you would expect of the species. But WCMM are not known for aggression, no matter what type they are. It does not make much sense that they'd be harassing larger fish when smaller fry are present. 

One thing I wonder, is the tank covered ? If not, you may have lost them to jumping out. I am making covers for my tanks.. because from time to time I have found a dried up little fish or shrimp or even snail, that's managed to get out and died as a result. Though you would not expect it to happen often.

If they were harassed, it's quite possible the fish died of stress. Are there shrimp in the tank? If so, they are quick to scavenge dead fish, so you might not have seen any bodies. If there are no shrimp, I'd expect to have seen at least some bodies if fish have died. Healthy fish usually don't eat a dead tankmate right away. Yes, they'll eat dead fish, but usually I'd think you would have seen them picking at a corpse or two. 

If it isn't harassment, it's hard to know why you have fewer neons and cardinal minnows now. But I have one theory. Perhaps they were genetically inferior and simply did not live very long, though I would still have expected to notice a dead body or two. These fish are quite inbred and it is very common to see both visible deformities and other problems related to hidden genetic weaknesses. Often the only 'sign' is early death. There are no wild caught minnows.. they're all commercially raised. They're now on the endangered species list in China, because most of the wild stocks are very low or missing entirely from where they were first found.

The cardinals, now that they are fewer in number, may be hiding more because they are nervous. They are a schooling species, and prefer sufficient numbers of their own species to swim with. 

Though they will swim along with the other minnows and neons, they tend to maintain groups of the same type. Like two groups of people who are walking along the same sidewalk at the same time, but only talking to their own group while they do so.. if that makes sense ? 

Have you seen the Gold ones being pushy with the other two species, or are they mainly pursuing each other ? If they're in breeding condition, such behaviour would be quite normal for them.. males do compete for females, but are not known for fighting or doing damage to each other. 

Neons can also have genetic problems.. many of the fish raised commercially have a number of genetic issues which are due to long term inbreeding. 

Inbreeding, especially over many generations, will tend to bring out and concentrate recessive genes. Though this is often how new variants are developed, it leads to a number of undesirable and even dangerous genetic traits as well. Many problems are not visible to the naked eye, only those leading to physical deformity are usually noticeable. 

I have long believed that inbreeding is a primary cause of many 'mystery' deaths or early deaths, in our aquatic pets. For that matter, in many other animals also. 

Consider some dog and cat breeds that have very short life spans compared to others, or known genetic health problems that are breed related. Purebred Persians are very popular, but they have the shortest life span of any purebred cat. A healthy indoor cat lives an average of 14 -15 years now, but a Persian on average lives less than 10 years, and they have a number of health issues.

As for canines, just one example would be English Bulldogs; one of the least healthy breeds, with multiple health issues, including a lot of gut problems. They often live only 8 years though they are not a huge dog. The giant breeds, like Great Danes and the like, often live only 9 years or so, but many small dogs well live into their teens. This is due to the genetic choices imposed on them by man. Some breeds simply would not be able to survive if they were left to their own devises, rather than being kept by human beings.

Genetic weakness as a cause is only my opinion, and it might not be why some of your fish vanished.. but I do believe it's a very common cause for things like this that have no other obvious explanation.


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## ppaskova (Apr 27, 2010)

Thank you for your explanation. Yes the tank is covered (mostly) with the glass top. Also I do have amano shrimps in the tank, this is why I never found the bodies. The fish in the tank I have: WCMM (cardinals and golden), neons, rummy nose tetras, razboras, guppies and one female platy. Also couple of corries and pleco. So I don't thins=k any fish I have there is aggressive to each other. Very possible genetic issues or maybe I changed the light 1 month ago to high light and regular top with glass see through one, they got stressed or very little chance hiding in the plants as those started to grow after light change.


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## Fishfur (Mar 4, 2012)

I would not expect higher light levels to make a drastic change in either behaviour or numbers. Though if fish are very shy, it might stress them a bit at first to have stronger light.. in which case I would expect they would spend more time seeking shelter under plants. But they should have grown used to it fairly soon, I would think. And plants growing faster and larger should make for more hiding places, not fewer.. unless there has been a lot of foliage loss at the bottom of the plants, leaving fewer low level hiding places. But the fish you've lost are not bottom swimmers.. they're mid to top level swimmers as a rule. 

The other species you mention should not be a problem either. Shrimp certainly explain the lack of bodies. You will probably never know for sure what happened, but genetic issues are one explanation that I do think makes a lot of sense. Unfortunate.. but it happens, I think far more often than most of us would think.


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