What the heck is "HO"?

HC stands for 'Hemianthus callitrichoides'. Its the smallest known aquarium plant, and is good for making a short green carpet on the bottom of the aquarium. It seems to do well in lots of different conditions, but it does best with lots of light and regular fertilization. In my experience, carbon dioxide fertilization is not necessary, but it definitely speeds up growth. It can take a while before it starts growing well and it is also easily uprooted by bottom dwelling fish if it hasn't had time to establish a good root system, so it does require some patience. Although it's not really a difficult plant, I'm not sure I'd recommend it to someone who is just starting with aquarium plants unless they are really dedicated to learning about the hobby. Also, it's not very common in pet stores. Unless your store has some people that are really into aquarium plants, you're not likely to find it there.

You can click this link (Google search for 'Hemianthus callitrichoides') if you want to learn more about this plant.

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I'm assuming that by "What the heck is 'HO'?" you meant to write HC instead? HO stands for 'High Output', and it refers to a type of fluorescent lighting (very similar to compact fluorescents). Basically, HO fluorescent lighting uses higher wattage (usually along with skinnier bulbs) to produce more light than a "normal output" fluorescent bulb of the same length. If you want to know more about HO lighting, just ask.

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