Before you take the plunge and purchase one of these delightful, adorable and very intelligent little monkeys, DO YOUR HOMEWORK!!! I can not say this enough.
Many longtime breeders, handlers and even veterinarians do not have or give out the correct information about the day to day life and care of tiny monkeys.

First: Marmosets & Tamarins CAN NOT eat store bought infant formula. Our human formula is specially formulated for the needs of humans NOT primates. Human babies need extra iron in their formula, primates DO NOT!!! To much iron leads to a deadly disease called Hemochromatosis (iron overload) damages the liver, heart, pancreas, endocrine glands and joints in small monkeys. Iron build-up in these organs causes cirrhosis, diabetes, irregular heart rhythms, weak heart muscle, arthritis and leads to death at around 7-8 months of age.
You may purchase the correct infant primate formula from our website:marmosetmom.com

Second: Marmosets and Tamarins CAN eat practically ANYTHING we eat with the exception of onions and garlic (which leads to anemia), spicy foods and too many sweets. Marmosets relish sweets but like any youngster they will hold out if they know they will get a sweet treat so make sure they eat a balanced diet and keep treats at a minimum. 

I can not tell you how many times someone has called me with a 6 month old marm that the breeder told them could not have veggies or meats. NOT TRUE!! Vegetables are good for them, cooked sweet potatoes, squash, cooked potatoes, peas, broccoli, peppers, cauliflower, pumpkin, cucumbers, leaf lettuce, green beans, corn, carrots, celery, etc. and they LOVE meat, chicken, steak, fish, crab, crickets, mealworms. 
Fruits of any kind. Bananas, watermelon, apples, pears, mandarin oranges, pawpaw, grapes, peaches, plums, strawberries, blueberries, kiwi, cantaloupe, etc.
They also like pastas, rice, cereals, oats, scrambled or boiled eggs, cheese, popcorn, nuts, etc.

*The younger (6 weeks) you introduce your little one to these foods the better eater they will be.

FEEDING SCHUDULE: 0-4 weeks-Infant primate formula (marmosetmom.com)
                                       4-5 weeks-Infant primate formula mixed with yogurt (any flavors) cereal and Marmoset powder diet (marmosetmom.com) smashed bananas, apples and sweet potatoes from my finger. 
                                       5-6 weeks-Apples, cheese, dry cherrios, cooked chicken, carrots, peas, beans, cauliflower, broccoli, sweet potatoe, bananas. 

Have fresh water available at all times and add an extra bottle of 100% fruit juice for the day once a week. I use Hi C.

SUPPLEMENTS: If you feed your monkey a proper well balanced diet with lots of variety then a lot of supplements are not needed. However, Vitamin D3 calcium is required for healthy bones and to prevent Metabolic Bone Disease.  A Vitamin D3 Calcium MUST be added after weaning from formula at least 3 times per week. I add it everyday just incase my marms don't eat everything on their plate. It can be sprinkled over food, added to yogurt or anything you know your little one is going to eat.

LIGHTING: You can add all the supplements and feed the best diet, but without the PROPER lighting a marmoset/tamarin can not survive in captivity!! A marmoset/tamarin NEEDS FULL SPECTRUM LIGHTING, UVA & UVB. This can be a rather expensive light $70-$90 but in comparison to the monkey and the vet bills you will encounter it is nothing.
*NOTE-The 10% strip light they carry for reptiles is NOT going to cut it. 

STOOL CHECK: it is very important to have regular stool checks for parasites. Monkeys like any other pets can have or get internal parasites (worms). 

SPAYING AND NEUTERING: I can not express enough how important this is! Fixing your monkey will help them live a longer, healthier and happier life. Not only will it help your pet not to become sexually frustrated when it reaches puberty but it will also greatly reduce or stop unwanted behaviors. Spaying/neutering should be done at 6-8 months of age.

HEALTH CONCERNS: Humans with viral infections should not be around Marmosets and Tamarins. A common cold can be deadly to a small monkey. Childhood diseases like measles, chicken pox and mumps are also fatal to a small monkey. Shingles and Cold sores cause by the Herpes Virus are extremely dangerous and cause fatal encephalitis. Humans with HIV or other immune system suppressing diseases should not own primates. 

Also, I have heard of many breeders out there saying these little monkeys do well with children. Nothing could be further from the truth. Marmosets and Tamarins are some of the most jealous of all primates and want your full undivided attention and will not share you with your children or grand children! Some even have trouble sharing their human mommy or daddy with another household pet. 

Can you cope with aggression - and sharp teeth?
No matter what you have been told, ALL MONKEYS BITE! Biting is a primates expression of anger and nothing you can do will change that. And teeth removal is not only harmful but CRUEL and it doesn't remove the danger: a toothless monkey can still cause painful injuries. For the protection of both the monkey and people, you must keep your primate from contact with any and all strangers -- that includes children, neighbors and relatives. In many states, health departments will destroy a monkey that has bitten to test for rabies.

REMEMBER, EVERY MONKEY IS AN INDIVIDUAL. THEY ALL HAVE THEIR OWN LIKES AND DISLIKES. ONE OF MINE LOVES GREEN BEANS AND ANOTHER LOOKS AT ME LIKE I'M TRYING TO GIVE HIM POISON, LOL.