Know About Bunaken National Marine Park
General Information
The  Bunaken National Marine Park was formally established in 1991 and is  among the first of Indonesia's growing system of marine parks. The park  covers a total surface area of 89,065 hectares, 97% of which is overlain  by sparkling clear, warm tropical water. The remaining 3% of the park  is terrestrial, including the five islands of Bunaken, Manado Tua,  Mantehage, Nain and Siladen. Although each of these islands has a  special character, it is the aquatic ecosystem that attracts most  naturalists.
The waters of
 Bunaken National Marine Park are extremely deep (1566 m in  Manado Bay), clear (up to 35-40 m visibility), refreshing in  temperature (27-29 C) and harbor some of the highest levels of  biodiversity in the world. Pick any of group of interest - corals, fish,  echinoderms or sponges - and the number of families, genera or species  is bound to be astonishingly high. For example, 7 of the 8 species of  giant clams that occur in the world, occur in Bunaken. The park has  around 70 genera of corals; compare this to a mere 10 in Hawaii.  Although the exact number of fish species is unknown, it may be slightly  higher than in the Philippines, where 2,500 species, or nearly 70% of  all fish species known to the Indo-western Pacific, are found.  
Oceanic currents may explain, in  part, why Bunaken National Marine Park is such a treasure trove of  biodiversity. Northeasternly currents generally sweep through the park  but abundant counter currents and gyros related to lunar cycles are  believed to be a trap for free swimming larvae. This is particularly  true on the south side of the crescent-shaped Bunaken Island, lying in  the heart of the park. A snorkler or diver in the vicinity of Lekuan or  Fukui may spot over 33 species of butterfly fish and numerous types of  groupers, damsels, wrasses and gobies. The gobies, smallish fish with  bulging eyes and modified fins that allow them to attach to hard  surfaces, are the most diverse but least known group of fish in the  park.
Biologists believe that the abundance of hard corals is crucial in  maintaining the high levels of diversity in the park. Hard corals are  the architects of the reefs, without them, numerous marine organisms  would be homeless and hungry. Many species of fish are closely  associated with particular types of corals (folious, branching,  massives, etc.) for shelter and egg-laying. Others, like the enormous  Bumphead Parrotfish, Balbometopon muricatum, are "coralivores" and  depend on hard corals for their sustenance. Bony mouth parts fused into  an impressive "beak" allow these gregarious fish to crunch corals like  roasted peanuts.
Some 20,000 people live on the natural resources of Bunaken National  Marine Park. Although there are inevitable conflicts between resource  protection and use by people, the Indonesian government is taking a  fairly unusual and pragmatic approach to park management. The idea is to  promote wise resource use while preventing overexploitation. Local  communities, government officials, dive resort operators, local nature  groups, tourists and scientists have played an active role in developing  exclusive zones for diving, wood collection, fishing and other forms of  utilization. If successful, Bunaken Marine Park will stand as an  important example of how Sulawesi, and the rest of Indonesia, can work  to protect its natural resources.
Accommodation and Transfer
On the island you have the choice amongst a number of homestays, with  rates starting at around Rp. 80 000 per day and person incl. fullboard.  If you only go for the cheapest option don't complain afterwards if the  water in your (bathroom) doesn't get filled up regularly, or food  isn't quite as nice as you had hoped for. Life in North Sulawesi in  general isn't as cheap as in other regions of Indonesia, and most things  on Bunaken have to be brought in from Manado. Depending on the season  even fish can be pretty expensive. Better think twice before you try to  bargain down prices which are already cheap; for the locals it could  mean the difference between being able to eat 3 or only 2 meals a day,  or buying school books for the children or not.
Some of the dive operations on Bunaken are offering more upmarket  accommodation, even hot showers (Living Colours, Cha Cha Nature Resort).
Some guesthouses ("homestays") on Bunaken:
Pangalisang Beach: Lorenso's Homestay
Liang Beach: Panorama, Nelson's, Papa Boa
There are a lot more...
Bunaken's much smaller neighbour Siladen only offers few accommodations. Most popular among budget travelers seems to be Martha's Homestay.
The most upmarket resort within the boundaries of the Bunaken National Park is Siladen Resort & Spa  which started operations in 2003. The eco-friendly luxury boutique  resort places high emphasis on the protection of the Marine Park and the  environment.
 The  public boats from Manado to Bunaken are leaving daily around 2 p.m  (depending on tide), except Sundays, from Pasar Jengki near Manado  harbour. Back from Bunaken to Manado usually early in the morning,  around 7-8 a.m. Even on Sundays there might be boats, just go to the  harbour and ask people there. To charter a boat is about Rp. 150,000 -  200,000 OW. If you want to go to Siladen it is better to inquire first  at the harbour, but usually there are several boats as well. The fare to  Siladen is also Rp. 15 000.  
Bunaken - Scuba Diving
A  growing number of dive centers is operating from the mainland around  Manado and directly from Bunaken Island. Generally spoken you should  rather pay a few dollars more and go for safe and experienced operators  than just choose the cheapest option. Tank fillings can be a problem,  and headaches after each dive give you a clear sign that your dive  operator saves money on filters; better go somewhere else if you  experience this. 

In  general diving standards in North Sulawesi are high, as is  environmental awareness among the dive operators, especially the ones  who have formed the North Sulawesi Watersports Association,  NSWA. The NSWA has made significant strides in improving the management  and conservation of Bunaken National Park and surrounding marine  ecosystems and in conferring concrete benefits of tourism to the  villagers living within the park. Many of its members have spent a lot  of their money and time for various ecological and social achievements  within the park. This has not gone unnoticed; the Bunaken National Park  has received the "Tourism for Tomorrow Award" and the "UN Equator Prize".
Unfortunately some stupid backpackers still think that they know  everything better than these international organisations and refuse to  pay the entrance fee to the National Park. If you are planning to do  this, please stay away. You are not welcome - the National Park needs  support, not ignorance!
A few 
Bunaken Dive Operations (just a few):
Living Colours Diving Bunaken:  Dive center and resort on the eastern side of Bunaken; idyllic  location, nice and professional team, relaxed atmosphere, good food. Hot  water showers.
Cha Cha Dive Lodge Bunaken:  Small and intimate dive resort, also on the eastern side. Run by an  Irish-Italian/Japanese couple. Excellent food, hot water showers.
Two Fish Divers Bunaken: PADI operation based at Pangalisang. Two British instructors, recommended for courses.
Bastianos Resort & Diving Center:  located on Liang Beach, western side of the island. Since April 2004  the dive center is managed by Indonesian instructor Frans Rattu.
A few 
Manado Dive Operations (not complete):
Eco Divers Manado have their base at at Kima Bajo Resort  north of Manado. From there it's just around 15 minutes by boat to  reach the famous sites of the Bunaken National Park. Modern and  well-organized dive center. Highly recommended dive trips to Lembeh  Strait can also be organized.
Since April 2009 diving at the nice and friendly 
Tasik Ria Resort Manado (about 20 minutes by car from the city) is run by 
Tasik Divers, with all new boats and equipment.
Celebes Divers: Nice resort south of Manado, run by Italians.
Minahasa Lagoon Resort:  One of the most upmarket (dive) resorts in North Sulawesi. Located at a  beautiful bay about 30 km south-west of Manado. Very well run,  excellent services, even small things are very well taken care of.
LumbaLumba Diving: Dive center with own cottages based in Tasik Ria. Run by a Dutch couple.