Originally Posted by stiltman
Thanks for your input. I will be checking out that link. Although my wife and I really enjoyed the dwarf indian puffer we had. He was in my 75 with a couple dwarf frogs and a dozen rainbows. Everyone got a long well until an ich catasrophe. I had the puffer for about a year. Fascinating little guy and this species does not require any salt in the tank. Anyway...I'll check out that link.
I do not have the pleco yet. Merly, he wants to get rid of it and I need an algae eater. I am interested why you suggest I stay away from him? Ich carrier?
I believe my well water is well suited for Cardinals and I guess for that matter Neons. My water is soft and slightly acidic.
I read that Cardinals prefer "low light" tanks, but almost always see them in beautifully planted aquariums. I know nothing about keeping live plants, but may be up to that challenge. This seems to be the exact opposite of a good home for a Cardinal though because a good planted aquarium will need strong lighting for at least 8 hours a day? Right?
Does all the vegetation provide hiding spots for them?
Anyway, as you suggested I am trying to take into account the basic water requirments for these fish. The dwarf puffers are said to be comfortable in 72-82 degrees. This might mean they could potentially be housed with either Neons or Cardinals. And, yes, don't worry I will not be mixing them.
I found on Dr. Foster and Smith: European farm raised Cardinals. Perhaps these are more hardy then wild caught? They better be because they are more than twice as expensive the regular guys.
Thanks again for the input.
You're certainly welcome. Here's some more suggestions/ideas to answer your latest questions.
First the pleco. I simply think a 12-18-inch fish is too big in size and too big a problem for a 75g tank. My smallest setup at present is a 70g and I can't imagine a pleco in it that was anywhere near that big; maybe a species that max out at 5 inches or just under. And when I say 18-inch, I'm supposing this is a species that will (if it is healthy and in a suitable environment) grow to 18 inches, given that it's 12 now. But not knowing the species... Nevertheless, I would find another home for it. Plecos contribute a considerable amount of waste to the aquarium, and have quite an impact on the bioload. I'm not meaning to suggest that your regular maintainance is not up to par, but it is more effort to maintain a healthy community for the cardinals and corys with that large a fish sharing the close quarters. Enough on that, on to more interesting stuff.
Cardinals, Paracheirodon axelrodi, are not always easy fish (and judging from the posts by a lot of aquarists on this forum, neither are neons--they seem to have a very short life in many aquaria), but with your water parameters you are a major step ahead. I've kept cardinals and their close relative the green or false neon, Paracheirodon simulans, for some time (12+ years) and in my view the wild caught fish are better. I only recently (last October) acquired some tank-raised cardinals, and have three left out of 9. I have all the wild-caught cardinals, and the P. simulans (in another tank) that are also wild caught.
Any idea of the pH and hardness of your water? I have my cardinals in pH 6.4 at present, with 2-3 degrees GH. Cardinals are known to develop internal problems such as calcium blockage of the kidney tubes when kept in harder water; I've never worried because my tap water is 0 or at best 1 GH, and I actually add calcium and magnesium to raise the hardness just a tad to provide some mineral for the good of the other fish. Cardinbals can tolerate warmer temperatures, and make excellent companions to discus because of this, but also seem (in my experience) to do well at normal aquarium temperatures of 78F. Neons tend to fare better slightly lower than 78/79F.
Baensch mentions that cardinals appear to have a light phobia at least in the fry. This probably stems from their habitat which is quite dark due to thick aquatic vegetation and overhanging trees and other vegetation that keep the waters shaded. This brings us to the plants--an article in one of the issues of TFH in 2008 had photos of cardinals in their native habitat in the Orinoco basin [this being the "Columbian" form] and as the author, a native scuba diver and photographer pointed out, cardinals are always found in small groups (6 or so) among plants, or where the aquatic vegetation thins or is absent, they congregate in larger groups of 50 or more and cluster around fallen branches and overhanging roots. The water is stained like strong tea due to the tannins from submerged plant material, wood and leaves and such. I've frequently noticed my cardinals behaving similarly, separated into small groups among the plants.
I have about 1 watt of full spectrum light over my aquaria, and they are moderately thickly planted. You can see this in the photos under "My Aquariums". The cardinals are in the 90g in those photos, the P. simulans in the 70g which has more floating plants. As mine live for years in such conditions, I must conclude the light is not distressing them. I would expect things to be different if I had a planted aquarium with plants requiring CO2 and thus more light, 4+ watts per gallon. I have always taken a somewhat low-tech approach to planted aquaria: no CO2, plain gravel substrate (Nutrafin Plant-Gro sticks next to the larger swords which are heavy root feeders), twice weekly liquid fertilization with Seachem's Flourish Comprehensive, and full spectrum light of 1 watt per gallon intensity. The lights are on timers and on for 13 hours a day, and I think this could be reduced to 10 or even 8. I stock my tanks fairly heavily which provides CO2 that balances the light and nutrients, and the key to success is balancing these three. I like the results, and I'd recommend a similar approach if this is the look you're after.
There are two forms of cardinal known, the Columbian and the Brazilian. The former is found throughout the Orinoco basin, and the latter throughout the Rio Negro system in the Amazon basin. In the late 1990's, the late Dr. Jacques Gery, who knew more about characins than anyone alive, determined that there are indeed two morphologically different forms, and further research would hopefully decide if one is a subspecies or they are distinct species. I haven't yet been able to track down any follow-up work. They are certainly different in appearance. The Columbian is somewhat chunkier, and the neon line ends at the adipose fin; the red below the line does not extend as far under the belly as on the Brazilian form. The neon line on the Brazilian extends just past the adipose fin, and the fish is slightly longer when mature than the Columbian form. Having both, I prefer the Brazilian, as it's a bit more colourful due to the longer and therefore slightly straighter neon line and has a bit more red. This form is close to the P. simulans, where the neon line extends into the caudal peduncle at the base of the caudal fin and is consequently straight [the line curves a bit on the cardinals], although the underlying red is not near so brilliant. Interestingly, these two species occur together in their Columbian range; they are closer to each other in their DNA than to the neon. Two years ago a fellow member on this forum, Heiko Bleher, discovered the fourth "neon" deep in the Solimoes region of northern Brazil. DNA studies show it is more closely related to the original neon, but all four species are definitely the same genus.