The siphons are out! The clams are already working and busy filtering the water. The are spewing out green globs out of their siphons! When I zoom in on my camera I can really see the pumping action! Green water goes in, dead green goo goes out. The snails and shrimp are already standing by to munch on the expelled green goo.

I wonder how long it’ll take the little guys to power through the green water. Days? Weeks? Hopefully not months?!
I’ve got about 13 gallons of water and 10ish small baby clams. I found a citation on Asian clams:
“Among other freshwater bivalves it has the highest rates of filtration rates (up to 1.3 liters/hr/clam), food consumption and growth of any species (MacNeill 2012).”

 

Tiny clam photography is hard. This is a picture of one of the bigger clams turning itself on its side, siphons on full blast as it buries itself in the substrate. Cool. Please ignore the photo-bombing bladder snail in front.

 

All of a sudden 4 clams buried themselves into the substrate. Only 7 clams are visible now. A bad storm is approaching with lots of thunder and lighting- a big pressure system. My kuhli loaches are going nuts as they are sensitive to the weather. I wonder if the clams are too. The clams that buried themselves are about 1/2 below the gravel line. I’m impressed they went that deep. As long as they can breathe and eat, it’s none of my business!

I managed to take a picture of one of the burrowing clams. The arrow is pointing to its “foot”, the translucent white gooey thing. Just above it is its shell. It’s pretty deep!

 

Clam math? 🧮 🤓 I have a 15 gallon fishbowl with about 13 gallons of water in it. Let’s say each clam can siphon 1/2 cup per hour. That seems like a modest estimate based on observation. I have 11 clams and 1 very small clam. I’m going to round down to the pumping power of 10 clams. 10 clams can filter 5 cups of water an hour. 🧑‍🎓 That’s 7.5 gallons of water a day which is a little over 1/2 the water available in the bowl. Technically I should start seeing more clear water in 48 to 72 hours 🤷‍♀️ I know for sure that these clams have more biomass than the daphnia and they have a physical/mechanical advantage in consuming waterborne organisms compared to the daphnia. Please feel free to contribute your thoughts! 😂

 

Very interesting and thanks for documenting the experiment! What species of clam did you get and where did they come from? I'd like to do some research on their use in aquariums and garden ponds.

 

The species I got was called Asian clams “Corbicula fluminea”. I bought them from a local guy who just happens to sell them on amazon and eBay. He lives about an hour north of me but I decided to keep it simple and order online. All of the clams arrived alive and healthy. The order was for 10 “baby 1/8” clams” and I got 12 clams and they were all bigger than 1/8” except the smallest- so the clam salesman was very generous. They are an invasive species but there is some debate if they are a danger to local fauna. They do reproduce quickly, but local bivalves seem to exist in abundance along side these invasive clams. As for adding them to your own garden pond, that’s more of your own ethical judgement call. Since they are invasive there’s a chance they could infest local waterways from your pond- but at the same time, these clams are probably already there!
The clam salesman claims he sources these clams from local Florida waterways which local fish and wildlife authorities have no rules against collecting these particular clams. Then my guess is he raises them in tanks and sells the numerous offspring. I read that one clam can produce 68,000 offspring in a lifetime! 😱

 

Clam update! I woke up this morning and all but ONE clam has buried itself. This experiment is going to be short on observations if this is going to be the case. I did get a picture of some clam action and It’s interesting from what I’m observing.
It hard to see here but it appears that a clam has buried itself and is expelling its green goo waste under the substrate. That’s a lot of algae! I hope the green water is providing a nutritious snack for the clams and they do well. I don’t want them to suffocate or starve or otherwise die. I need to trust the process and trust the clam! They are buried deep but the STS is relatively large and light that I think they’ll be okay. The few clams I caught burying themselves did it in a matter of a couple of minutes so there wasn’t much of a struggle.

There has been no appreciable impact on the green water as of yet. We may be looking at weeks in terms of progress.

 

I've read you can feed them bread yeast after the green water is gone.

Article in portuguese:
- - Planeta Invertebrados Brasil -

 

I've read you can feed them bread yeast after the green water is gone.

Article in portuguese:
- - Planeta Invertebrados Brasil -

I’m not too worried about food sources after the green water gets cleared up. My tank is very bioactive and there are no filters. I’m hoping this will be a big green feast then trickle down to a more average amount of food. This particular clam species can “lick” around with their foot and eat detritus and mulm on the bottom of the tank.

 

Clam siphon action video!

 

Observations on Day 3: All of the clams are completely buried except two. One clam is sitting happily on top of the gravel and another has re-emerged half way up, siphon pumping. I’m not worried about oxygen levels in my tank. The tetras and kuhli loaches zoom around the middle of the bowl all day with vigor. They are never at the top gasping for air. Shrimp are busy eating green goo expelled by the clams.
I tested the ammonia and it’s at 0 ppm. Everyone’s alive and well! (the water is still green though😑)

 

Super interesting. I do think they will run out of food if you keep them all in that bowl.

 

I don’t think so because there’s a constant influx of food into the bowl. The food cycle goes from the fish food, to the fish to the shrimp and snails to the bacteria and algae and then the clams and finally to the plants. The green water represents an overload of biomass and I’m trying to transfer that biomass into the clams. I have no filter so biological material isn’t being removed that way. These clams can also eat detritus and mulm with their feet. The only way biomass is removed from the bowl is plant trimming.

 

Quote from the main “Fish Bowl” Journal:

I’m starting day three with the clams. They started off very healthy when I first got them (from what I can tell) and have mostly buried themselves since. Some clams “pop up” for a while then bury themselves again. From my reading these are hardy clams and other people’s experiences seem to be that if they are happy, they stay that way. One aquarium keeper started off with 10ish clams but when he broke down his large aquarium he had 200 clams! So far all of the clams are alive (as best as I can tell) and happy. It might take a minute, but if I observe where they ought to be, they usually spit out a plume of green goo every so often. It usually takes 5 minutes of constant obseration. Mostly it’s looking for signs of the clams: They’ll expell the green goo and it’ll accumulate against the glass or as I posted before they expell their green goo into the substrate making an out of place green patch against the glass in the gravel. A lot of people seem to nervously dig them up to check on them. The more experienced clam keepers implied that “you’ll know” if they die. So far, all clams seem alive and well! I’ll do an ammonia check just to be sure.

Edit: Ammonia is 0ppm.

 

Day 4. No improvement in overall green water conditions. All clams buried except two that are hanging out on the top. I wonder if the green water is too thick and established for the clams and aquatic plants to get ahead of it at the moment. I know that a little more plant biomass will be able to smother the green water algae. I am seeing ejected green goo from the clams on the surface of the glass and substrate. Snails, shrimp and kuhli loaches seem to relish it. I am worried about the kuhli loaches a little. They seem to be digging around where the clams should be buried. I think they’re after the green clam mulm. One kuhli was even pulling the shell around of one of the clams camping out on the top. Kuhlis never seem interested in their actual food 😑. Bladder snails also seem to be harassing the clams a bit too. When I first put the clams in the bowl, the snails swarmed the clams and ate the dark brownish algae off their shells. Cleaned up, I can see why Asian clams are also called “Golden clams”. The clams seem to like to do “touch up” cleaning from time to time. I’m waiting until next Wednesday (1 week) to see if there’s some improvement in green water. If not I’ll go a big water change, 50%+.

 

Clam down! I have my first clam death. After so many days one dead clam out of 12 isn’t too bad. This clam was acting strangely for days now in hindsight. This is the clam pictured above. This clam surfaced a few days ago and was the source of the bullying from the fish, shrimp, snails and kuhlis. I think the tank mates knew death was near. They could smell it. I took it out and inspected it last night. It was closed but something seemed ”off”. It smelled “briny“, but not “dead” or like rotten eggs like I was warned it would be when dead. I think as of last night it was still alive. Well, clam death is very obvious if they open this much. The other clam sitting on the surface is being ignored by its tank mates, and its siphon is pumping away healthily. The dying clam had no siphon action. It was just in stasis.
In hindsight the signs of “clam death” seem much more obvious: surfacing, being picked at by tank makes, no siphon action, no movement at all (the other ‘surface’ clam rotates from time to time) and odd behavior different from all other clams. Here’s hoping progress on the green water will continue!

 

From Bon Appetit:
Press together the shells of any that are open. If the shell doesn't close, the mussel is dead

 

Yeah, it’s definately dead. It was closed last night when I inspected it but it was WIDE OPEN this morning ☠
I removed it. The other clams are buried and happy 🤷‍♀️

 

Dead clams smell worse than ANYTHING.

 

LOL, then I must have caught it just after the moment of death. Last night, it was closed and a little “briny” smelling like I said. Nothing bad at all. This morning it was dead and wide open.

 

Day six! not much to observe. The water is still green and I can see what the the lone clam on the surface is doing. It’s healthy and doing clam things (which isn’t much of anything 🤷‍♀️). I really think the clams will mature nicely and give me excellent clear water- someday. I think they’re just too small at the moment. The clams probably won’t cure my green water woes in the next weeks.
I’ll be cutting back on food in general. There’s a constant “rain” of mulm to the bottom of the bowl. I need my scavengers to clean up. My local fish store suggested I feed everyone half of what I’m currently feeding and to change it up a bit. I’m also going to try putting in a pothos plant to help clean up the green water as a temporary solution.

 

After a weekend outing I came back and did a BIG water change (75%). I think the clams needed a head start over the gravy-thick green water algae. I have a few progress pictures. Since the big water change, the water has become more clear over the next few days. I think the clams are definitely helping here!
BEFORE water change:

DURING the water change:

1 day AFTER the water change:

2 days AFTER the water change:

TODAY!

These are big improvements! I will claim total victory over the green water when I can see the wallpaper on the other side of the bowl. Yay clams!

 

The clams have claimed total victory over the green water. My water is beautifully clear. I can see the texture of the wallpaper behind the bowl.

I still have one clam that sits happily above the substrate. I should name him/her. Any suggestions? 😂

 

I wanted to add this quote from another thread where I discussed my current experience with freshwater clams. It’s a good summary of my thoughts so far. I’ll give updates over time and I’ll have a stronger opinion as the months pass:

The question was: ”What are you feeding your clams?”

“I’m experimenting with that! Since the clams are filter feeders, they feed on floating organisms and waterborne detritus in the water column. The clams have cleared out the “cloudiness” from my water, which was probably the green water algae. However, despite the clearness of my water, when I look at it in the light there’s still floating detritus like “dust in an attic” floating around. This is likely mulm in various stages of decay from the fish, shrimp and the hundreds of snails in my fish bowl. This floating debris is what my clams are currently feeding on.
It is important for me to note for you that I DO NOT have a filter in my tank. I strongly believe that some people have trouble with clams because of their filters. If I had a filter, the floating detritus would very likely be cleared from the water column in a matter of minutes, probably starving the clams as a result in the long term.
I am also trying to “target feed” my snails. I’m adding cucumber and blanched vegetables floating above where I know the clams are. The snails then eat the vegetables and I get a steady “rain” of mulm and fine vegetable debris where the clams live in the substrate. So far my clams are happy and healthy. I’ve only had one death out of 12 since I introduced the clams and that clam died in the first couple of days.

I honestly recommend trying pothos if you want a quick and easy low-tech solution. There is so much mixed messages (and maybe even a little misinformation) about clams I’m not sure I’m ready to give them a full endorsement yet. But I’m working on that! To be honest though, I have had nothing but a very good experience with the clams and my water couldn’t be more crystal clear.

Before:

Several Days After:

 

Let's give your plants some credit! Green water and plants compete. Green water algae takes up light, nutrients, CO2 and raises pH so plants are forced to use the less desirable bicarbonates. With a water change, you immediately give plants a major "leg up'. Once the plants get growing well, they will take care of your green water.

Clams are helpful and awfully interesting, but I would not count on them. Like you, I found daphnia totally useless.

 

The plants did help. Why I credit the clams was the speed of how fast my water cleared. Before the clams, I changed the water and it would slowly become cloudy again. After the clams (and water change) I was having a notable improvement in water clarity in a matter of 6 hour increments. It was obvious that the green water was being eaten. The plants however make the bowl habitable for the clams.

 

Development! Two clams have re-surfaced. Since I’ve got my clams all but one buried themselves into the substate. The clam on top of the substrate has been healthy (it’s reactive and closes its shell when disturbed) and was siphoning water this whole time. The other clams have been buried and hidden. I was able to see some clam “activity“ in the form of eaten green algae against the glass under the substrate where the clams buried themselves.
The clams that came out of hiding appear healthy and are busy siphoning the water. It’s nice to get an update on how they are doing. I took some pictures. There was some mulm against the glass but you can still see the clams. So far, so good!

 

Update! I was pruning my fishbowl and doing a big water change and I spotted a few clams! They were reactive and healthy. Happy clams! 4 months on and the clams are a healthy and beneficial part of my aquarium. No problems to report. At this point, I would recommend clams for your natural planted tank 👍

 

They survived! What a blessing. I'm definitely interested in incorporating them into my tanks!

 

Thanks for this separate thread!

Clam questions!
How big do these get?
Will they have enough to eat after your plants starve out the green algae?
Do they dig enough to let the potting soil get to the surface?

 

Thanks for this separate thread!

Clam questions!
How big do these get?
Will they have enough to eat after your plants starve out the green algae?
Do they dig enough to let the potting soil get to the surface?

The clams “digging” isn’t an issue. They go down once and they do not stir up the dirt at all. Golden clams get to be about 1 inch to 1 1/2 inches maximum. I believe my dirted bioactive tank creates enough algae to keep the clams alive. The clams also eat any floating organic matter in the water.

 

Hello! I made the account because of how thankful I am for your experiment, thanks a lot for this!
I also have pond with Asian clam but I think my fish kept chomping them (lots of Tilapias and 2 Catfish, most already larger than my palm) so I introducing Freshwater Mussel (Pilsbryoconcha exilis) and they thrive very well with 0 death since I introduced them half a year ago. The pond become way less smelly and clearer after they settled.
Yesterday I do a water change and found that some of the Asian clam still alive, I'll put one into my outdoor n filterless tank that now became green. Thank you for reminding me of their use.

 

No problem! I see then from time to time when they pop up and they’re an important part of my tanks now.