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Pet Rats/Weight Loss in Special needs Rat.


Hello Debbie!
I'm writing you an email today to ask about my rat Momo. My regular vet is away for 1 month and a half, and I can't get him before he leaves in two weeks.
I have a male 'special needs' rat, Momo. He is at least two and a half years old. We got him with a number of problems. He has a head tilt, asthma and is very hard of eyesight at this point. When we adopted him, it was expected that we'd keep him comfortable for the end of his life, but I am pleased to say we've had him for a year and a half now.
Recently I've noticed that he's lost weight. He still has a appetite, but is not as voracious as eater as he was  before. He no longer hids his bowl anymore and isn't as fiesty with his food as he once was.
I've been feeding him more fatty, nutrient rich treats (peanut butter, cheese, veggies, he doesn't eat meat because of health issues though) but I'm worried. I can't go broke over him, but I'd really love to know if you could help me figure out the cause, and any treatment, if possible.
Also, if it helps any, he's a fancy rat. He is on his own. I'm not a new rat owner, and have had three rats before, (a pair and an other single one) all males.

Hi Stephanie,
What is his basic diet?  Rat blocks? Seed and grain mix?

The best supplement for rats who aren’t eating well or who are losing weight is powdered soy infant formula from the grocery store.  (The liquid form goes bad too fast.)  The brand doesn’t matter because they’re all about the same (Wal-mart's store brand is cheapest).  They contain pretty much all the nutrients a baby needs, and they are 50% fat, so they help put the weight back on them fast.

Mix a little of the powder in water, pedialyte, or juice.  You can mix it as thick or as thin as you need to.  Thick encourages intake of nutrients and can be fed off your finger, thin encourages intake of fluids.  Most rats love it and will lick it out of a little dish. You can also give it with an eyedropper or syringe. You can also soak or mix ground rat blocks in it.

The infant formula is nearly a complete diet for rats. The only nutrients the formula is short on for rats is the B vitamins.  When giving the formula longterm, add enough liquid vitamin B complex supplement to supply 1 mcg of B12 to each scoop of formula, or you can add ¼ Tablespoon of nutritional yeast (available at health food stores) per scoop of powder.  If your rat doesn’t like it, try adding a tiny drop of vanilla extract or other flavoring.  If that doesn’t work, try adding some whipped cream or ice cream.

If the formula is pretty much all your rat is eating, give one scoop of the powder in the morning and another scoop at night.  One scoop a day is enough if the rat is eating other foods.

I highly recommend my Rat Health Care booklet which includes this and a lot more helpful info.  You can find more info about the booklet on my website at on the Books page.

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Debbie Ducommun


I can answer any questions about pet rats, but you will probably be able find answers to simple questions more quickly on my website at If you have a life-threatening emergency you can try calling me at 530-899-0605. I am not usually on the computer on the weekend.


I have been "The Rat Lady" since 1985 and am recognized as one of the world's experts on pet rats. I have 3 published books and already answer lots of questions about rats daily.

President of Rat Assistance & Teaching Society

I am a monthly columnist for Pet Business magazine, and my writing has appeared in other magazines. I have 3 published books.

BA in Animal Behavior

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