Snails suffering, but fish fine. A puzzle.

[LFNfan]

Hi,

For a little while now (several months?) my Nerites have been not themselves.

Start fine, then over time increasingly lethargic, then kaput.

The start to finish of this cycle seems to be getting quicker such that the latest batch of five have become lethargic over the course of a month and three have now ended up on their backs. They were all racing around when they first arrived. My first couple of nerites I had for a good year till they both croaked, in quick succession.

Any ideas what could be causing this? Seems like something negative is building up over time and not getting cleared.

I don't think I have any copper anywhere in the tank, change approx 50% water weekly. I dose 2N per week and corresponding micros. Water about 23C. RO water from Spotless Water in Watford.

Welcome any thoughts / advice.

 

[xZaiox]

Are they getting enough food? You also say you use RO water, what is the level of dKH and dGH that you aim for? Do you re-mineralise the water to add calcium?

 

[LFNfan]

Thanks for the reply!

Food - great question - quite a bit of diatoms on the glass. So that exclusively really. Kept my first nerites alive for a year. I recently bought some ebay mineral blocks to supplement - but not a hit - in the tank for three days and not a sniff.

Trying to lower my dGH and KH but currently measuring around 7 and 4 respectively (RO cut with tap water) . Before RO (when the original nerites were alive) they were about 18 and 12 (really hard tap water). But that was less ideal for the plants.

Many thanks!

 

[xZaiox]

How well formed are their shells? Do you notice any small holes in them?

It sounds like you're actually doing exactly what I am with my own water, my tap is also 18 dGH and 12 dKH, and I cut it by 2/3rds with spotless water, giving 6 dGH and 4 dKH. I only have the one nerite in my current tank, but she's been alive and happy for a few years now. I also have a large population of malaysian trumpet snails, bladder snails and ramshorn snails. They're fine with the hardness. If you have diatoms on your glass then that should indicate food availability for them.

I'll leave this one for someone else to answer because I'm not really sure. I think the water hardness is sufficient (based on my own snail population). I will add that nerites can sometimes be a bit finnicky when first acquired... Are you purchasing the smaller baby ones? They're often harvested from the wild and they're not always adjusted properly to the store's water parameters. I found the really young ones can sometimes have high(ish) death rates, but once they've become established they're quite hardy. It could maybe be worth asking your fish shop (or wherever you get them) to tell you when they arrived to the store, and where they were shipped from, whether they're wild caught etc.

This last step may not be necessary, but I deworm most things going into my aquarium, mainly because I've had much lower death rates since doing so. I'm not 100% sure if snails need deworming, but I know wild caught ramshorns can carry flukes, and a lot of African snails tend to carry parasites as well (can cause things like schistosomiasis), and I believe that some nerites come from Africa. I may be being overly cautious on this part, but it might something to think about.

 

[seedoubleyou]

They're often harvested from the wild and they're not always adjusted properly to the store's water parameters.

Nerites breed exclusively in Brackish water don’t they?

 

[seedoubleyou]

Might find an answer in here?

Nerite Snails at top of tank/ keep dying

Hi - I’m wondering if anyone can offer some suggestions about what to do with my Nerite Snails. About three weeks ago I bought 10 freshwater nerite snails which I put in three different tanks. Since then I’ve had four of them die. One crawled out of the tank and was found on the floor the...

www.ukaps.org

 

[LFNfan]

How well formed are their shells? Do you notice any small holes in them?

Thanks xZaiox. the shells are not bad - certainly no holes. I think the hardness is OK for them.

Are you purchasing the smaller baby ones?

I'm getting via eBay. I've had a few lots over the past 18 months. First pair of zebras from LFS lasted a good long while. Second pair of 'onions' from LFS lasted...maybe 3-4 months. First eBay set of horned (much smaller) 2/5 still going fine (the bigger ones) after a month or so. Latest ebay lot of horned a week ago (same supplier) big one and small one no longer with us, rest hanging around the bottom of the tank on the glass by the gravel (this is not a good sign).

 

[xZaiox]

Nerites breed exclusively in Brackish water don’t they?

There are so many different varieties of nerites, but I believe a lot of them live their lives in streams connected to the ocean. They start life at the sea, and travel upstream. Because of this, there are fluctuations in the parameters that they experience, and I guess it's difficult to replicate this accurately at home. It's why a lot of them will be wild caught, and many won't take the sudden acclimation to the fish shop's water very well.

Thanks xZaiox. the shells are not bad - certainly no holes. I think the hardness is OK for them.

That's a good sign then. Do you run CO2? How about the tanks pH?

I'm getting via eBay. I've had a few lots over the past 18 months. First pair of zebras from LFS lasted a good long while. Second pair of 'onions' from LFS lasted...maybe 3-4 months. First eBay set of horned (much smaller) 2/5 still going fine (the bigger ones) after a month or so. Latest ebay lot of horned a week ago (same supplier) big one and small one no longer with us, rest hanging around the bottom of the tank on the glass by the gravel (this is not a good sign).

Do you have many fish in the tank? Any shrimp? If they're lasting multiple months then suddenly going, and also have intact shells then I'm wondering again about the possibility of them needing more food. As I said earlier, I find nerites are usually quite hardy once they're established in the tank. How many nerites do you typically keep together? One by itself won't require much food, but if you're keeping a colony then it quickly adds up. How big is the tank?

 

[LFNfan]

Might find an answer in here?

Thanks @seedoubleyou

some good points in here, and I think I'm doing OK on them - but not all.

• no CO2
• shells good
• shipped humid, and were clinging to the inside of the container, not rolling around, not stinky (I hate smelling snails - it just feels...wrong)
• acclimatised to new water over a few hours per seller's instructions
• after acclimation I sunk the container and let snails make own way off it - did not pull off (I 'tickle' the snail's foot so it retracts if I want to move it - v rare)
• 'the most effective advice - purchase from another source' ... I could try this next!

Don't know if this is something or nothing, but for the last while I've got a bit lazy with how I water change: first bucket-full is 100% RO perhaps a bit cooler than the tank water, second bucket is 50/50 RO and tap plus epsom salt. Over the two buckets it's the ratio I want. I doubt this approach would be the issue, right? Either way I've gone back to splitting the RO and tap proportionately in both buckets as of this evening. Try and eliminate that variable.

 

[LFNfan]

How about the tanks pH?

around about 7.5 as far as I can tell (liquid test kit). Can't get it lower for the life of me!

How many nerites do you typically keep together? One by itself won't require much food, but if you're keeping a colony then it quickly adds up. How big is the tank?

five or six in a 70 Litre. There's always plenty of diatoms on the glass. My first set of zebra nerites also roamed the hardscape, but the more recent ones stay on the glass.

Nerites breed exclusively in Brackish water don’t they?

I have a feeling this breeder breeds in the UK in brackish tanks and then probably ships out. Possibly transfers to freshwater and then ships out.


Maybe I'll try another supplier and go back to the zebras (a bit bigger so perhaps a bit hardier). See how that goes.

Happy to also provide some other food - welcome any suggestions.

 

[seedoubleyou]

Don't know if this is something or nothing, but for the last while I've got a bit lazy with how I water change: first bucket-full is 100% RO perhaps a bit cooler than the tank water, second bucket is 50/50 RO and tap plus epsom salt. Over the two buckets it's the ratio I want. I doubt this approach would be the issue, right? Either way I've gone back to splitting the RO and tap proportionately in both buckets as of this evening. Try and eliminate that variable.

This may well be your issue then. Even if it’s not the cause, it’s best to keep your maintenance practice consistent.

 

[LFNfan]

Well, my tank still seems to be a bit of a kill-zone for snails.

The eBayer I got the horned nerites from kindly responded and said they live in freshwater, very low nitrate tanks.

I'm dosing N 2 / week at the moment (have been for the past 3 months), but think I'm going to take that back down over a few weeks back to N 1 / week which is more or less what the tank started at c. 18 months ago, and see if the snails recover, or at least stop dying quite so quickly. Possibly interesting to note that the first two zebra nerites I had lasted in N1 water for 12 - 14 months. They both died about a month before I upped the dosage to N2, as I seem to recall. So who knows.

Will keep an eye on the plant growth during this time. My tank is low tech, not especially heavily planted, but with quite a few floaters.