Blackwater Tanks and Water Conditioners – Common Aquarium Questions

As aquarists, we want our aquariums to be the best environment possible to support the beautiful fish, plants and inverts we love. One recent email presented a FAQ topic that may be helpful to some of you out there on the topic of water conditioning.Mike asked:

What water conditioner would you recommend to replicate the water conditions in the Amazon Basin that would be ideal for discus and freshwater stingrays? When a product is called water conditioner, does that mean it is used to turn tap water into water that is ideal for fish? responded:

Making a home aquarium the ideal environment for the fish you want to keep can sometimes be daunting with all of the products available on the market today. Some fish can live and thrive in variable conditions, while others prefer or need specific conditions for optimal health and appearance.

Water conditioner” is a general term for any water additive that alters the existing chemistry of the water. They are used to make the conditions in the aquarium friendly for fish in general, especially after water changes and other disturbances. These products usually do several things such as dechlorinating water, detoxifying ammonia, and help the fish to maintain or recover electrolytes caused by being stressed amongst other things. Each product may be a little different from the next, but they are all intended for the same basic purpose.

Some specific types of fish benefit from additional additives or equipment that helps you to mimic water conditions from their natural habitats. For example, discus and freshwater stingrays prefer soft, acidic water which may be created by using an RO unit to purify your tap water and adding a pH buffer to set the pH where you would like it. Seachem’s Discus Buffer would be ideal for buffering the pH on the low side where these types of fish prefer it. It will also help to reduce the hardness of the water if you’re not using RO. Additives like Blackwater extracts and Discus essential can also be beneficial as they add essential minerals, nutrients and elements that are found in their native waters.

Feel free to send us any questions you may have about your tank.

Until next time,


Another Fish Nerd Vacation – The Toronto Zoo

Hi folks,

Aoudad Sheep at Toronto Zoo Desiree’s blog about fish nerd vacations brought back memories of a trip I’ve taken recently. In October of last year I was fortunate enough to find myself in our neighboring country to the north. On our way to Montreal to visit a friend, my girlfriend and I stopped at the Toronto Zoo that we have read so much about. We knew that it was the largest zoo registered with the AZA (Association of Zoos and Aquariums) and one of only five accredited zoos in Canada, but we still couldn’t contain our amazement once we arrived.Anthias

Fish and aquarium enthusiasts will be pleased with the zoo. A new exhibit in the Australia region of the zoo features several different aquariums representing the reefs bordering the continent. One of these contains live soft and stony corals, another is home to species of fish not considered reef safe (angels, butterflies, etc), and one contains several dozen moon jellyfish. They even have several aquariums dedicated to freshwater crayfish (the really cool ones from Australia). Other aquariums around the zoo include an enormous Lake Malawi exhibit, South and Central American biotopes, and one with endangered cichlids from Madagascar. Cichlid Exibit

The entire zoo sits on 710 acres of land. There are over six miles of walking trails, and we walked almost all of them in a single day, which unfortunately did not leave us much time to sit and enjoy any single exhibit. The zoo has everything for animal lovers. There are over 5,000 animals at the zoo from almost every corner of the world. Herp lovers will enjoy the many species of snakes, lizards, and amphibians that the zoo has on display.Snake at Toronto Zoo

So if you ever find yourself in the Toronto area, take a day to check out the zoo. You will not be disappointed.

Until next time,

Conservation Update: Oriental Weatherfish (Dojo Loach, Misgurnus anguillicaudatus) established on the Iberian Peninsula; Food Trade Decimating Reef Fish off Southeast Asia

Hello, Frank Indiviglio here.

Two articles addressing fresh water and marine fish conservation issues were published this week:

Oriental Weatherfishes in Spain

According to an article in Biological Invasions, the Oriental Weatherfish (native to eastern Russia, south and Southeast Asia) is now well established throughout Spain’s Ebro River delta, and has a foothold in the Onyar River as well. This is of particular concern because over 80% of the Iberian Peninsula’s freshwater fishes are already considered to be threatened, with introduced species outnumbering natives in most rivers.

Last year, studies of the eel fishery in the Ebro River revealed that 8.2 tons of non-target fish, representing 17 species, are captured along with each ton of eels (elvers) harvested.  Approximately 40% of these fish perish before they can be released.

Fishes of the Coral Triangle

Reef fishes are becoming increasingly popular on restaurant menus throughout Southeast Asia and mainland China.  Particularly hard hit are species native to the waters bordered by Malaysia, Indonesia, Papua New Guinea, the Philippines, East Timor and the Solomon Islands.  Known as the “Coral Triangle”, this region is home to 75% of all known species of coral.

According to a recent Conservation Biology article, spawning aggregations of local species have declined by 79% in recent years, largely due to over-fishing.  Groupers, 26 species of which are endangered, have suffered the most.  Conservation efforts are complicated by the large number of countries having interests in these waters.

Thanks, until next time, Frank Indiviglio.

For further information on the natural history and captive care of weatherfishes, please see:

Fish Nerd Vacations: How a Marine Biologist Spends Time Off

Hey Fish Bloggers!

Desiree here.

It’s the dead of winter….so invariably my thoughts go to planning my summer vacation.  Some fortunate colleagues of mine have already taken winter retreats to Florida or elsewhere.  But as I pour over maps and travel catalogs, and look at pictures from those friends in Florida, I have realized that you can’t take a fish nerd on vacation. 

It doesn’t matter where you go, the power of “fish nerd-dom” is impossible to overcome in any environment.  I think those of you who fall into this category know what I mean and are laughing hysterically right now.

If you are somehow not in this particular category of nerd – Imagine the last time you went somewhere, anywhere with a real “fish geek”.  In any city we nerds visit there’s ONE question… “Where’s the aquarium?”  We’ll go, not shut up once about anything we see, critique it according to where we’ve worked or visited in prior trips, and then move on to the next one.  Think camping is safe?  NOPE.  Wherever we are, we’re looking for a stream or pond where there are fun rocks to turn over or aquatic plants to identify and more likely than not – all sorts of mundane things (like riffles) to photograph.  OOOH LOOK – A cichlid in a ditch!!! 

And don’t even think of taking a beach trip!  Hobbyists are bad enough, but your trip is hopeless with a “Marine Biologist.”  We’ll instantly revert to stories of field studies, trawling trips, dive sites, and the obligatory drunken college boat trip.  We’ll wax philosophic for what seems like hours on the ramifications of eco-tourism, native fish collection, global warming and garbage vortices, much to the annoyance of those who aren’t quite so passionate about the subjects.

Non fish nerds can’t relate to any of this seemingly insane behavior and are instantly bored out of their minds and think “Here we go again!”  Well, like I’ve told my own non-nerd husband – you’ll have to grin and bear it.  Fish nerds are a passionate bunch and there’s just no way to take a “normal” vacation with any of us.  It’s best just to sit back and enjoy the ride, besides you might just learn something.

 I think New England looks good this year – so many rocky shorelines and tidal pools to fall into!!  Maybe I’ll turn over Plymouth Rock to see what’s under it.  It’ll be great!!

Until Next Time,


Finding Love the Anglerfish Way – Anglerfish breeding

Melisa here. Well, it is that time of the year again. It’s a bit chilly these days. What better to do than snuggle with the one you love or find someone to love…right?

The Anglers and frogfish that are commonly kept in our aquariums have much less complicated rituals.  Just before mating (usually 8-12 hours before), the females of many common types will begin to fill with eggs, typically 40,000 to 180,000!  Their abdomens become distended, making them quite buoyant.  When the male comes along he nudges the female’s abdomen, stimulating her to move to the surface where spawning occurs.  The eggs are usually released as an egg raft or veil that drifts along for a few days before dropping to the sea floor after the embryos hatch.  Post-planktonic frogfish (1-2 months old) take on the appearance of a perfect tiny Frogfish, but often display bright defensive colors!

Some species actually tend to the eggs, protecting the clutch until they hatch. Lophiocharon trisignatus males attach the egg clusters to their bodies until they hatch.  Some species hold the eggs not only to protect them, but also to lure prey closer with the eggs as a prospective meal for the clueless prey!

Deep sea anglerfish of the superfamily Ceratioidea probably have the most interesting way to find the” love of their life,” to say the least.

When scientists first started studying ceratioid anglerfish they were confused why all they appeared to capture were female anglerfish. It was also noted that most of these anglerfish that were studied had some type of parasite attached to them. It was later revealed that the “parasite” was actually what remained of the male anglerfish. With some further investigation scientists were able to tap into the secret lives of these anglerfish.

At birth the males are programmed to detect scents in the water. They immediately begin their search for a female in the deep dark depths of the ocean. As they mature, the males digestive system shuts down, making the males incapable of feeding themselves. If he does not find a female he will die. Assuming he finds a female he takes a big comp and attaches himself for life. The male anglerfish releases an enzyme that fuses his body with hers. From the moment they are one the male becomes an autotroph living off the female. As time goes by the male begins to degenerate, leaving only lump with is gonads enclosed to release sperm when the female releases her eggs. This extreme mating ritual assures that when the female is ready to release eggs they will be fertilized. 

If you know of any other bazaar mating rituals in the fishy world I would love to hear about them.

Until next time,