At the top of that page, you'll see several types of Plecostomus Catfish, and you'll probably notice that they resemble each other. Plecostomus usually eat lots of algae and even wood. Click here for more about Plecostomus Catfish.

Continuing to scroll down that same page of "Scavengers", you'll see several types of Catfish including some labeled Synodontis Catfish, which are very good aquarium fish. Click here for more about the Upside Down Catfish, which is a species in the Synodontis genus.

As you continue to scroll down our page of "Scavengers", you'll see some dwarf catfish called Armored Catfish. Most of these Catfish are in the genus Corydoras, so they are often called Cory Cats, and they too are generally very good aquarium fish. Click here for more about Cory Catfish.

Finally toward the bottom of the "Scavenger" page you will see the Siamese Algae Eater, which is a wonderful species that eats lots of unwanted algae. Click here for more information about Siamese Algae Eaters.

Although the Siamese Algae Eaters and the Plecostomus Catfish eat lots of algae growing on the ornaments in an aquarium, there is a better way to control algae. Click here for more information about getting rid of the algae growing in an aquarium.

Many beginning aquarists mistakenly think that scavenger fish will keep their aquarium clean, but this is certainly not true. Scavenger fish are no substitute for a well organized regular maintenance schedule. Click here for more about an Aquarium Maintenance Schedule.

If you have a filter with a BIO-Wheel in your aquarium, then you do not need gravel. Fish do not need gravel, and most fish will never miss the gravel. If you like the appearance of gravel, and many aquarists do, then put a thin layer of gravel that is no more than 1/4" thick.

When gravel is 2" or 3" thick, it's almost always filled with grungy waste and uneaten food. Fish almost always do poorly in aquariums with thick layers of gravel.

But fish bowls and plastic ponds need a thin layer of gravel, because the gravel increases the surface area available for the beneficial bacteria to grow on. Gravel with beneficial bacteria is called cultured gravel, and cultured gravel is important in fish bowls and ponds without a filter. Click here for more information about cultured gravel.

Your Betta will tolerate cooler water better than the guppies did, and a Betta will do fine in your aquarium without a filter or an bubble stone. In fact Bettas prefer still water, so it might be best to remove the filter and the bubble stone. Click here for more about keeping Betta Fish.

You can use the advice given on this web site for keeping a Betta in a fish bowl. Click here for more information about keeping fish in fish bowls.

What a great combination: (1) Pet Department with a MaRS system full of good fish and (2) a Ria ready to provide lots of good information and advice.

Now back to your question. I don't know where to get a Salt Level Test Kit. I do know that the MaRS system manual recommends adding Aquarium Salt to the MaRS system once each week. The MaRS system automatically replaces some of the water in the MaRS system each day, and after a week the Aquarium Salt is mostly gone, then you add another dose of Aquarium Salt.

So once a week the salinity goes way up, when you add the Aquarium Salt, then each day the salinity decrease as the MaRS system changes some of the water. This is really ideal, because the change in salinity lessens the number of pathogens in the MaRS system but does not harm the fish. Click here to read more about Aquarium Salt.

Now I'm going to guess that you are concerned about measuring the amount of Aquarium Salt in the water in the MaRS system. But this is not necessary. Just pour the recommended amount of Aquarium Salt into the sump tank in the MaRS system once a week as scheduled. The amount of Aquarium Salt is about 1 Tablespoon per each 5 gallons of aquarium water in the MaRS system.

Red Sores is Sign #4 on our list of Signs of Stress and Disease. Click here to read the list of Signs of Stress and Disease. If your fish show any of the Signs of Stress and Disease, we recommend that you give your fish the Recommended Treatment. Click here for more about the Recommended Treatment.

Your pond sounds like my pond. Click here to read about my small pond in a barrel.

On the other hand, I have noticed many times that fish become skittish, when too many tank mates disappear at one time. Maybe this is a natural fear. You know something like, "What's happened to everybody?" Most fish seem more comfortable in a big group of tank mates.

I would recommend you put the extra fantail back in the aquarium and see if the other fish's behavior changes.

The link to the address of our facility is given at the bottom of each page in this web site, but we do not accept visitors or customers in our facility. We are not insured or zoned for retail sales, and our crew is not properly trained to wait on customers. Our crew is very well trained in caring for fish and in shipping fish.

I apologize if this reply disappoints you.

A year or two ago I gave a close friend a large fish bowl with some White Clouds, Ghost Shrimp, Java Ferns, and a few small Snails. She had some problems with her fish bowl, and she reported to me that she was certain it was caused by the Snails.

I told her, "Oh no, that just doesn't happen. really it never happens. Something else has happened, and it probably won't happen again. But keep a close eye on your fish bowl, and maybe you will find out what is really happening."

Well she did keep an eye on her fish bowl, and she became all the more certain that the Snails were causing problems. I tried to persuade her that it must be something else, but she was convinced it was the Snails.

Now comes your report, Bronwyn, and my confidence is slipping a little bit. Maybe some Snails do cause some problems. But it must be very rare. I tend to think your Betta died for some other reason, then the Snail was caught looking guilty at the scene of the murder.

I wouldn't recommend anything to children that I thought had even a small chance of ending in disappointment. But there is hardly anything that I can recommend that will always work and never cause a problem. Right? I apologize to you and your son.