Questions about eastern newts.

I have a couple questions about two eastern newts that I have had for about two months now. First, they live in a ten gallon tank with two ghost shrimp and two guppies, and I decided to leave the tank unplanted since it was going to be in a dark, low traffic room. Is this acceptable? The newts seem perfectly happy and healthy (great color, eat regularly, and are active), but recently a long vein has appeared on Beatrixes' (the female newt) left side starting at her front leg and stretching down almost a third of the way down her body. She doesn't seem ill or act like she has an injury, but I just want to make sure this couldn't be eventually life threatening.

It's hard to say, could you post a picture?
There are plenty of plants that would survive low light levels, Java ferns and Hornwort spring to mind, but there are lots of others.
Eastern newts are notoriously difficult to keep healthy in captivity for any length of time, so to me, getting their environment right from the very start seems vital. They seem to do best in mature planted tanks with added almond or oak leaves, possibly to help keep fungal infections at bay. A few years ago lots of Eastern newts were imported into the UK and although I didn't buy any I know a few people who did. Even with the correct care, not a single one survived, some were seemingly healthy one day and then dead the next for no obvious reason, so I would say you need to do things by the book for them to stand any chance of surviving long term.

Well, its kind of hard to get those plants around here, but I do have an ample supply of water lettuce and water hyacinth plants, along with duck weed. I would quarantine all of these for a little bit, and enough light would probably come through my window to keep them alive. I'll also try to get a picture of her as soon as possible.

Water hyacinth Water lettuce and Duck weed good plants to use. They suck up nitrates really well and most newts seem to like hanging out in the trailing roots. They do need a lot of light to do well, but if you have a good supply you could replace them regularly.

Okay, thanks! I'll see about the other plants, my mom has a pond full of all that stuff so I shouldn't have to worry about contamination. Thanks again!

Hi,
Despite what everyone else has said I have found noto's to be very easy to keep... I have 4 of them and they feed themselves completely and are relatively low maintenance and independent. However, you do need LOTS of plants, my noto's love hiding under them and taking shelter. It would also be a good idea to provide some quiet spaces for them to get away, they seem to be a very shy species sometimes. In terms of lighting I would recommend getting something even if its very dim just to encourage natural behavior.