Are guppies super sensitive?

i have a 20 gallon tank with 2 panda mollies, and 2 male guppies. just 2 days ago i went to petco because i wanted to buy 4 female guppies(2 of them already died). my water parameters are 0/0/30. this isn’t the first time i’ve had guppies die. last month again, i bought 5 guppies and 3 of them died. but everyone else in my tank looks so happy and no issues at all. are guppies prone to dying or female ones atleast? are they not hardy fish? i could use some insight. i acclimate for about 20 min and leave the lights off for an hour when they enter the tank

 

2 possible things with this

1. The mollies are stressing the guppies out or bullying them when you're not looking

Or

2. The store has low quality guppies. Try going to a different store if possible.

 

fancy guppies are usually really inbred, meaning a lot of them are really frail and delicate.

 

While it's certainly possible that the mollies are stressing the guppies, commercially raised guppies are also notoriously difficult to keep alive longer than a month after you get them home. I'd recommend trying to buy some from a hobby breeder, or a locally owned store that buys from local breeders (the chain pet stores aren't allowed to buy locally).

 

Guppies aren't all that super sensitive really but look at them, they aren't the most robust looking fish either. A couple things, Guppies mature around 6 months, they live around 2 years or so, so adult guppies that you buy could be from 6 months onward and the clock is ticking. ideally they are still juveniles and just a 2 or 3 months though.

Females being live birthers can also face problems with growing fry and giving birth and this can kill a fish.

Water quality can have an effect on fish also when introducing new fish to an aquarium. They can have trouble acclimating, stress and die.

I like to do at least a 30% water change before introducing new fish to a tank, I like to get the nitrates low and the tank cleaned up in prep, then I float the bag and add some water every 15 minutes until the water in the bag has doubled and an hour has passed, so the temp is adjusted and the water has been moved closer to my tanks water, then net them out into the tank.
I don't lose fish this way, I lose fish by "plop and drop" which is dumping the water and fish into a net from the bag and then dropping the fish into a tank, and I lose fish if I haven't prepped the tank with a good water change and cleanup beforehand.

 

In general, commercial guppies are a bit weaker than those guppies bred at a serious private breeder. It's not really the different strains that are weak. But the way they've been raised is of importance. The commercially bred guppies are bred in mass reproduction and there's hardly some culling. So, they're not selected by quality anymore. Then you also must know that most commercial bred guppies from Asia are raised in water with more salt in it. After they're sold and shipped abroad, they won't be replaced in the same kind of water. This will already weaken them more.

I also like to say something about the actual age of those commercially bred specimens. They look older than they actually are. You may think that you're dealing with an adult specimen but actually, they're younger but raised in a fast way. It is possible to raise newborns in 6-8 weeks looking as being adults. But that needs higher temperatures, multiple feeding a day and a good water flow. If you don't mind investing a lot of money, you can really do the turbo growth method.

 

Last year in May, I bought my guppies all off ebay, 2 female green dragons, 3 blue dragons, 1 m, 2 f and 3 black Moscow 1 m, 2 f - all 3 diff breeders

I purposely let them all interbreed because I know from dogs that inbreeding for recessive traits makes the bloodline weak over time.

every single fish from those purchases did not last 1 year. I think at most 1 of them lived 6 months.

my blood line is half blue, half black Moscow traits

I'm not advocating mutts, it was just a choice I made after having soooo many bettas died because their bloodlins are so weak now due to overbreeding.

I just purchased today Purple Moscow to add to my bloodlines ( I wanna say generation 6/7 after almost 18 months of having guppies)

I have black ( few), now white!!!!/nearby clear - just had them develop into adulthood in last 10 days, some pink mosaics, a few 'true' blue dragons

3 light blue makes with flat tails from the Moscow blood line. 1 maleis half navy/half white with flat Moscow Tail - nifty looking.

Doing it the way I am, I do not know what my fish will grow into for at least about 4 weeks, but it makes it interesting. Most of them were outside for summer in tubs so they should be fairly healthy now.

I have around 30+ females and and still about 40+ males in 5 tanks. about 16 guppies in my 16 gallon cube.

I have a betta in there but will move him once my purple guppy comes in because I want purple bloodline to dominate and I will remove all males but purple one during that time so his bloodline will dominate in my existing one.

sorry my camera stinks - so no pictures. But i'll try tomorrow when lights are on tanks.

btw - I prefer Moscow tail. Dragons can struggle to swim much like many exotic betta types do. The weight of their fins is burdensome. Beautiful to look at though.