Sand Sifters, FW sel.   12/17/08 Hello Crew, Hope all of you are doing well. I am in the process of setting up a fw aquarium with a sand bottom. The deepest section will be in the back (about 1 inch). <Very shallow; obviously too shallow for plants. But zero risk of anoxic decay.> I plan on having rainbows, angels and Corys. I had been thinking about getting some Malaysian trumpet snails to help keep the sand sifted but am worried about getting too many. Could you please recommend a good fish that would accomplish sand sifting? <Decent-sized Corydoras will manage this just fine! Otherwise, I'd recommend perhaps Horseface Loaches (Acantopsis choirorhynchos) or Cherry-fin loaches (Acanthocobitis rubidipinnis). These are both reasonably gregarious, not especially aggressive loaches that spend much time burrowing and will of course eat any surplus snails they can catch. The Horseface loach is quite big, up to 25 cm or so, while the Cherry-fin is much smaller, less than 10. Loaches despise hot, still water, so do keep the tank reasonably cool (less than 26 C) and with lots of water movement. That would suit all your fish, even your Angels, which do rather well in strong (but not turbulent) currents provide they have upright roots and such to provide pockets of peace where they can rest.> Also, I have considered keeping a clown loach but read that they can get very large. <Yes, very; up to 30 cm, and need to be kept in groups of 6+.> Do they grow fast or does it take them a long time to get big? <Get to over 15 cm within three years, and then growth slow down.> And is it OK to keep them singly or in groups? <Groups. Actually a very difficult species to keep well.> Thank you so much for your help. Thanks, James <Cheers, Neale.>

Re: Sand Sifters, FW Thank you Neale, and could you please explain anoxic decay? <Decay of organic matter without oxygen; what happens in deep beds of sand or mud. Essential for completing the nitrogen cycle, allowing nitrate to be converted into nitrogen gas. Standard practise in marine tanks: called Deep Sand Beds or Live Rock. For whatever reason, freshwater aquarists have a paranoia about anaerobic decay, as if it's something that routinely kills fish. It does not.> Also, is one inch or less of sand substrate OK if I am not using live plants? <Enough sand for covering the glass and giving the fish something to root about in is fine. One inch is perfect.> I hoped by doing this it would eliminate some of the risk of dead pockets of gas. <"Dead pockets of gas" is the myth I'm alluding to above. May occur in theory, but as yet never seen/heard of any convincing example of anaerobic gas killing fish. It's normal in ponds (which have stinky mud!) and marine tanks (where anaerobic decay is encouraged because it IMPROVES water quality). Why freshwater aquarist get worked up about it eludes me.> Thanks again. <Cheers, Neale.>

Re: Sand Sifters Thank you again Neale, but I have read that sand substrate should be stirred up occasionally to prevent dead spots and the ensuing gas that could cause fish death. Is this something different? James <It's a good idea to stir the substrate periodically and siphon out any detritus. This is simply good maintenance. By removing organic matter (faeces, dead plant material and so on) you reduce the amount of organic decay in the substrate, aerobic and anaerobic. The cleaner the substrate, the cleaner the water, and the better the fish. Some aquarists (but no modern books) maintain that pockets of anaerobic decay can produce deadly amounts of hydrogen sulphide. While it is certainly true hydrogen sulphide can be produced in a deep, sandy substrate (around 8 cm/3 inches) there is no evidence the hydrogen sulphide can actually cause harm. Hydrogen sulphide is extremely reactive, and the tiny amounts formed in the substrate -- assuming a reasonable level of hygiene -- will react virtually instantly with the oxygen in the water, long before it has a chance to poison the fish. No-one worries about anoxic sediments in ponds; why do they worry about much less anoxic sediments in aquaria? It's a mystery to me. Melanoides snails will, in any case, render such discussions moot. They are extremely good sand cleaners, and work in fish tanks in just the same way as earthworms in gardens. Cheers, Neale.>

Scavenger Question   8/21/08 Hello Crew, <Hello,> I would like to know some suggestions for scavengers in my fish tank. <Stop. If you NEED scavengers, you are overfeeding. A properly maintained tank has NO NEED for scavengers. Indeed, expecting any fish to survive by "scavenging" is unrealistic. Bottom feeding fish like Corydoras need their own supply of good quality food, ideally offered at a time of day when other fish can't eat it before them, typically at night.> It has angels, platys, zebra Danios, and a Gourami. <Your Platies should happily be pecking away at the algae in the tank, and in the process will consume any uneaten food they find, assuming said food isn't rotten.> I don't want to go with snails but i don't know which kinds of loaches or catfish can tolerate the aquarium salt i put in the water. <Why are you putting salt in the water? None of these fish need salt, and long term some of them will be stressed by it. At best, adding salt is wasting your money. If you feel the need to fritter away your money, can I suggest you sprinkle the salt on the sidewalk, making pretty patterns. It will do much less harm there than in your FRESHWATER aquarium. The recommendation to add salt is old school and made (some) sense when we (the hobby) didn't really understand about water quality. Salt reduces the toxicity of nitrite and nitrate. But in a properly maintained tank you should have zero nitrite and less than 50 mg/l nitrate, so these chemicals aren't a problem. A lot of inexperienced fishkeepers get told by retailer to add "a teaspoon of salt per gallon" or some nonsense. This dosage will have no appreciable effect on parasites or bacteria, and the idea it's a "tonic" is garbage. Now, guess who recommends using salt? Correct: the salt manufacturers and retailers! Wake up and smell the coffee... you are being taken for a ride here. Even allowing for the waste of your money, salt places an osmoregulatory stress on freshwater fish. Your Platies won't care being quite salt-tolerant anyway, but the Danios, Cichlids and Gouramis are all true freshwater fish with limited tolerance for salt, and over time things like Dropsy are more likely to develop than otherwise. So stop with the salt!> Also, the leader Danio likes to chase my platys and the other Danios around. It sometimes (rarely) nips my veiltail angel's fins. How can i get rid of this problem? I have 5 Danios. <Danios when kept in too-small a group become nippy. It's what they do, and it's widely stated in decent (modern) aquarium books. End of discussion. Keep them in bigger groups and in a tank large enough that they can burn off their energy without getting frustrated. I'd consider 5 too few, and would recommend you double that number. That would of course mean the tank would have to be big enough for them, and certainly not less than 90 cm/3' in length. Danios just AREN'T fish for "small tanks". They are big and they are active.> Thanks <Cheers, Neale.>

Re:  Scavenger Question 8/22/08 Then should my tank have NO aquarium salt at all? <If you're keeping freshwater, then no, you don't need to add salt. That's why they're called "freshwater fish"!> I've noticed that before i started to add aquarium salt to my tanks my fish died constantly but now they don't die after i started adding salt. <Salt detoxifies nitrite and nitrate. So if you have an aquarium with poor water quality, then adding salt can help -- at least in the short to medium term. But in the long term salt causes problems (for example, Malawi Bloat, which happens when non-salt tolerant cichlids are exposed to salt). Hence your job is to get water quality right by stocking sensibly, not overfeeding, and having a mature filter that's up to the job at hand. Adding salt is the equivalent of fixing a crack in a wall by painting over it. You hide the symptoms, but the problems are still there, potentially getting worse...> The water quality was and is fine but they still died without the salt. <Post hoc ergo propter hoc? Simply because two things happen coincidentally in time doesn't actually mean they're connected. Pick up any aquarium book and you'll see no mention of adding salt to the water of standard community fish. Why? Because on balance it does less good than harm. But good water quality, and understanding water chemistry, is very important.> Also, how are goldfish affected by it? <Carassius species including Carassius auratus are relatively salt tolerant and do occur in slightly brackish water. That said, they live and breed best in hard, alkaline freshwater.> Thanks <Cheers, Neale.>

Re: Scavenger Question 8/22/08 Okay, I stopped the addition of aquarium salt into my aquarium. I would like to add bottom feeders. Since there still may be a little salt left in the water after the water change, is it still safe to add catfish or loaches to my tank? <Probably, yes. As ever, acclimate new livestock carefully.> If so, which loaches or catfish can get along with angelfish, Gourami, zebra Danios, and platys? I have food like algae tablets and such that they can consume. <Corydoras would be the best bets. Many species, ranging from the cheap and cheerful Bronze and Peppered Corydoras (Corydoras aeneus and Corydoras paleatus) through to more expensive and finicky species like Corydoras panda and Corydoras robinae. Can't really go wrong with any of them provided the water is clean and not too warm (few Corydoras like temperatures above 25 degrees C/77 degrees F). They are gregarious, so keep a group of at least three and preferably 5 or more specimens of whichever species you get. Whiptail catfish (Rineloricaria and/or Hemiloricaria spp.) are also peaceful and good value, and might appeal to you if you want something quirky. They are gregarious as well, though the males are territorial. Basically hardy, but like Corydoras, they do not like very warm water. Eat some algae, but primarily omnivores that feed on invertebrates and thrive on good quality pellet/algae wafers. I have a great fondness for Synodontis nigriventris, a schooling dwarf catfish from Africa; my only reservation is that it is sometimes a fin-nibbler, and not recommended for keeping with Angels. Otherwise a hardy and fun catfish (though very shy if not kept in sufficient numbers).> Thanks <Cheers, Neale.>