Acceptable attrition rate?

[nodding_dino]

Hi everyone,

I'd love to hear peoples thoughts on what you consider to be an acceptable rate of loss for small tetras, from a statistical perspective, not a moral one (I of course don't want to lose any), but am trying to gauge what is deemed typical. For context/background I have kept tropical aquariums on and off for over 30 years although primarily large SA/CA cichlids.

So assuming that you have an aquarium of suitable size, matured, with excellent (and stable) parameters (Amm/Nitrate/Nitrate/Ph/Oxygen saturation/temp), UV, good husbandry (weekly 50% water changes) and the tank being furnished with sufficient hiding places. If you introduced a group of say 20 young tetras would a loss of 1, 5, 10, 20% be typical?

I have been considering the impact of things like:

• Stress of moving/settling in
• 'Bullying' that comes with sexual maturity
• Inherent health issues (mass/farm breeding)

Fish were treated with a broad base treatment when they arrived in the tank.
No outward signs of issue, feeding well (mixture of foods), clear eyes, gills, normal behaviour etc.

Thoughts greatly appreciated - your real world experiences would be great

Thanks

 

[Ichthys]

Normal for me (seriously) would be zero deaths for a few years till they started to die of old age.

 

[nodding_dino]

Normal for me (seriously) would be zero deaths for a few years till they started to die of old age.

Thanks for your reply, and would that be based on a group of 5-10-20-20+? Or any number?

 

[Magnum Man]

When I was into fish, 20 years ago... you were doing good to keep a fish for a year... if they lasted a year, you were doing something right... now that I'm back into fish, I think the expectancy is you should plan on them dying of old age, if you do everything right... one of the on line sellers I use ( not really any local fish stores ) lists life expectancy... quite often smaller fish die sooner than bigger fish... & if everyone does their part in the supply chain... there really shouldn't be any early deaths, provided they survive shipping, whether that's around the block, or across the country

just for fun, that seller lists lifespan of Neon's at 4 years, & cardinal's at 5 years... BTW... I've never personally been able to keep small tetras, the last time I bought Cardinal's all 6 died in 2 days... but today I'm running RO water in almost all of my tanks... we have extremely hard, Alkaline water where we live... with the RO water I have 4 Congo Tetras, that ( crosses fingers ) seem to be doing good, going on 2 months... it's not their life expectancy, but beats 2 days, & the Congo's are still alive

so if you're giving the fish everything they need, & the supply chain did as well... I think they'll all live... if we're missing something, then I'm sure you'll see varying degrees of success

 

[nodding_dino]

Thanks Magnum Man, I think you're hitting the point for me. As these are new fish (and I have limited experience with tetras), I'm trying to figure out if I'm missing something (although like I said all tests, husbandry and environment seem spot-on) that drives loss as a result of their current environment or whether it is more likely they became susceptible to something during their time in the farm/supply chain en route to me? I'm being overly cautious to make sure I'm not missing anything (I don't think I am), hence the question about what would be an 'acceptable' rate of loss. All comments greatly welcomed!

 

[Ichthys]

Thanks for your reply, and would that be based on a group of 5-10-20-20+? Or any number?

Once you get them past a week or three (ie they came in healthy) I would expect that for any number that’s enough to not cause stress.
I wouldn’t keep fewer than about 10-12, personally.

 

[GaryE]

I see where you're coming from, Shipped tetras can have some losses, as can low quality fish. If I buy from my good lfs, that unfortunately buys the same stuff sold online, I calculate a 25% loss as reasonably certain. That's in the first 48 hours or so. Remember many farms use antibiotics to speed growth, and the fish you buy are on their own against a world of pathogens for the first time when they are shipped. Then they are crammed into bags and put on planes and trucks.

Buying from a large chain, up to 50% losses are possible. They will tell you it's your lack of a cycle to dodge responsibility. It's always the hobbyist's fault.

After that, if they don't have TB, they live at least 5 years.

If I get wild caughts from importer friends, any losses are a surprise, and lifespans under 5 years tell me I'm doing something wrong.

There is a lost art to buying tetras, where you go to the store and study each individual, looking for signs. If you see any disease or have any (and I mean any) alarm bells ring, you walk away. "I must have it now" is the perfect motto for disease buyers, not fish buyers. As we move to an online fish sales model, we're at the mercy of people we never meet, and buy fish we don't get to evaluate. I'm hoping to do a fish order early next week, sight unseen. Only the seller is a friend I trust absolutely.

 

[nodding_dino]

Once you get them past a week or three (ie they came in healthy) I would expect that for any number that’s enough to not cause stress.
I wouldn’t keep fewer than about 10-12, personally.

Super - thanks for the clarification - the group is larger than 12 and about a month in - hence my thinking that this could still be a hangover from their time before arriving with me - but again - I'm being super cautious so curious as to a 'baseline'. Appreciate the help

 

[nodding_dino]

I see where you're coming from, Shipped tetras can have some losses, as can low quality fish. If I buy from my good lfs, that unfortunately buys the same stuff sold online, I calculate a 25% loss as reasonably certain. That's in the first 48 hours or so. Remember many farms use antibiotics to speed growth, and the fish you buy are on their own against a world of pathogens for the first time when they are shipped. Then they are crammed into bags and put on planes and trucks.

Buying from a large chain, up to 50% losses are possible. They will tell you it's your lack of a cycle to dodge responsibility. It's always the hobbyist's fault.

After that, if they don't have TB, they live at least 5 years.

If I get wild caughts from importer friends, any losses are a surprise, and lifespans under 5 years tell me I'm doing something wrong.

There is a lost art to buying tetras, where you go to the store and study each individual, looking for signs. If you see any disease or have any (and I mean any) alarm bells ring, you walk away. "I must have it now" is the perfect motto for disease buyers, not fish buyers. As we move to an online fish sales model, we're at the mercy of people we never meet, and buy fish we don't get to evaluate. I'm hoping to do a fish order early next week, sight unseen. Only the seller is a friend I trust absolutely.

Thanks for the extensive reply, it certainly supports my thinking that this is a before (me) rather than after (me) problem. These were bought from an online retailer, a relatively large group and the first time (and honestly likely my last) purchased without a visit to the local store. Your point about wilds is interesting - I always assumed they would be more susceptible/fragile.

Its a mixed group of males and females, they are growing well, with some beginning to get good finnage and colour (and exhibiting mating behaviours) so I'm trusting the process - but will always err on the side of caution so wanted check-in with the community

 

[GaryE]

Wilds are generally more robust and healthy to begin with.

It's only natural for disease to spread with crowding, and there is enormous market pressure on farms to keep their prices as low as possible. That means severe crowding, and every trick in the book to accelerate growth. They need to move the fish to market as quickly as possible, and the large corporate buyers don't care about quality if they can sell the "units" before they die. Everything is speed - a race against poor practices. It's a shame, and it may kill our wonderful hobby. Heavy losses certainly discourage us.

It's taken me years to network, but I have a large fishroom without farm bred fish. I just gave up on their poor health. My local store owner is a wonderful guy, and even if it costs more, I buy dry goods from him. I won't buy his fish.

 

[nodding_dino]

It's taken me years to network, but I have a large fishroom without farm bred fish. I just gave up on their poor health. My local store owner is a wonderful guy, and even if it costs more, I buy dry goods from him. I won't buy his fish.

I buy from specialists wherever possible - so echo that. My foray into online is it seems a 'one and done'!!!

 

[Magnum Man]

one doesn't often see the tanks that suppliers use... here is a sneak peak... it's really a wonder that you can actually get healthy fish