Freshwater clam deaths. Help appreciated

[Formosa]

These are eaten here by the older generation here in the countryside. I dont eat them but i asked for some he had in the bucket he got the day before from the river. These can be found in the ditches pouring out from rice farms even, which is generally quite polluted from agricultural poisons.

Strangely i killed every single one. I am wondering what can be done as the larger species is kept in pet stores with no substrate to filter the water a bit...my substrate is river sand and am wondering if that may be why they die? Do they need a more muddy material? Second guess was maybe they need faster faster moving water? I see them in ditches and rivers, always lots of water flowing by at a decent rate.

These are the 3 species have tried. All died within a week, the medium ones died in 2 days

 

[FallenPepper]

Feed them pressed aglea right above them only way to know that they're eating

 

[Colin_T]

Poor water quality or chemicals like copper will kill clams.

They won't starve in a couple of days so check the water quality for ammonia, nitrite, nitrate and pH.

Don't use fish medications in their tank.

 

[Formosa]

Thank you both for you help

The water is rain water and no chemicals added as my main interest is invertebrates not as much fish. So no copper/fish medications

I checked ph is 6.1 (ranges 5.8 to 6.5 over the last few months). After water changes, it tends to level out to near 6 everytime.

I dont have tests to specifically test nitrites/nitrates but will ask next time i go to the city. I have the general test you add some drops of their chemical to a sample of water and color code. So far comes back clear, but understand they arent always the most accurate. The last 6 months have had 5 tadpoles and the clams only, 10 day water changes and he water runs through a stream of roots so i just assumed the water couldnt be that high in nitrates etc. Maybe i was very wrong!

After the clams died, I added 3 corydoras and 6 small shrimp. To add some life to the water section, they are all doing quite well. Added a few snails as well, which seem to be happy. So i dont think it would be a metal issue in the water. Or is that assuming too much?

Thanks for the info!

 

[Colin_T]

What is the pH and GH of the water that the clams come from?

If the clams come from brackish water or water with a pH above 7.0, or a high GH, then pure rain water with an acid pH won't help them and could kill them.

Regarding heavy metals, fish are much more tolerant of them than invertebrates. Copper can be used to treat fish for external protozoan infections but the same dose will kill all shrimp and crabs in a tank.

If the clams were kept out of water for any length of time before you got them, they could have damaged them. And if they got hot while out of water it would definitely affect them. They cook inside their shells if left out in the sun.

 

[Formosa]

Great, thank you!

I just went by the river to grab some water. The ph is 7.7! Pretty different for sure. Perhaps this is the reason. They were out of water when i brought them back for about 5 mins. Snapped a quick picture and in they went. I saw them moving, squirting and burrying themselves.

This tank is mostly for invertebrates, dont keep many fish. So very very careful not to add metals etc, the water is fairly clean.

One other variable i had forgotten to mention. There is (was) 1 fresh water prawn in there. About 5cm long. This species eats fish, tadpoles etc. But is it possible it can open up clams? I cant see it, but they are very aggressive. I put it in an outdoor area in our garden now as i have a few fish so needed to separate them.

 

[Colin_T]

Macrobrachium shrimp can't break clam shells.

Most invertebrates do better in water with a pH above 7.0. Water that has a lower pH will cause calcium in their shells to dissolve and become weaker.

You can add some limestone, shells or dead coral skeleton/ rubble to the tank to increase the pH so it is above 7.0.

You should also check the salinity (salt level) and GH of the river water you got them from. And keep them in water when transporting them.

 

[Formosa]

Great advice much appreciated! Im not sure how to check salinity, will ask the pet store next time i am in the city. I assume here isnt very salty as its in the mountains far from the ocean.


We never take them from the wild, they are just "rescued from a bbq" kind of. They were in water, but he likely washed them and stored them in tap water. Its well water here so no chlorine.

Thanks again for all your helpful advice!

 

[Colin_T]

If you are in the mountains there probably won't be any salt so don't bother about that.

If the clams were rescued from a bbq, they might have already been injured prior to going there, possibly even kept in tap water (as you mentioned). In which case, they are probably not going to survive anyway.

 

[Formosa]

Seems plausible. They were alive when i put them in the tank, but it is hard to tell if they were injured or not.

For now i think likely also my ph is way off for their natural habitat. Though pet shops keep them in the same ph as my tank (asked them yesterday) it may also have been the shock in changing environments so fast. All the info from you has opened my eyes to look at certain aspects more, will certainly help next time attempt them!

 

[shabash]

Just of note, if they did manage to survive the ordeal prior to you putting them in your tank, how did you acclimate them? Inverts are more “delicate” than fish and should be acclimated slowly. Preferably drip acclimated over a few hours. Wish you better luck in future with your bbq rescues.

 

[Formosa]

I had them in a bucket with the water they were given to me in. Then added water cup by cup for about 30 mins. Maybe 2 or 3 liters spread over that time. After, placed them in the tank. Perhaps that was too fast?

 

[Colin_T]

that is fine for acclimatising them